Hi Hugo! It took me a long time to answer you, but I wanted to do it, and I also wanted to keep the text to use on my blog 
Leeks are naturally drought-resistant plants.
Wild leeks grow in places ranging from dry slopes to extremely arid places such as cliffs and gravelly scree at the seaside, where they are among the few plants able to survive.
Everything about them indicates it:
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Their life cycle: they are perennial plants with winter vegetative activity and summer dormancy.
Except for their first summer. When plants are grown from seed, the plants grow for over a year (at least 15 months) before flowering for the first time.
In poor conditions, they may sometimes not be developed enough to flower (flowering which also induces the segmentation of the bulb). They then enter dormancy with an uncut bulb (round like an onion). In this case, they will flower at the end of the next cycle (therefore at least 27 months after germination).
Plants from cloves can also dry out without flowering, and go dormant in the form of onions. -
Their morphology:
In its evolution, the leek has chosen minimalist foliage to resist drought, thereby sacrificing its competitiveness for light.
Condemning it to arid places, without vegetation.
So they adapt to the drought, and produce minimalist foliage.
… etc.
The combination of minimalist, gutter-shaped foliage covered in pruina (a powder that has a water-repellent, but also shading/reflective effect), with the leaf edges and the central vein of the underside of the leaf being scabrous (a touch similar to a hacksaw), acting as capacitors for the morning dew.
This allows these dewdrops to slide along the leaf with almost no loss of water thanks to the pruina, and find themselves trapped in the leaf curl that forms the pseudo-stem. The pseudo-stem then acts like a water tower (we can see, several days after a rain, that when they are cut at ground level, some water flows from the pseudo-stem.)
When in dry conditions, leeks will lose their oldest leaves, located on the outside of the pseudo-stem. These will then serve as bark, protecting the plant from contact with the sun and wind.
(Let us remember that the leek growing season extends from autumn to early summer.)
When the seeds mature, the plant is most often already dry, and the flower stalk is disconnected from the root plate. The seeds, in order to develop, will then only need the water and nutrients contained in the stalk to complete their maturation.
When the flower stalk emerges, the foliage is sometimes partially or completely destroyed, whether by diseases such as rust, or by drought. This constitutes a new element capable of photosynthesis, with tissues less sensitive to rust than the foliage.
And in case of drought, the cylindrical shape, even more minimalist than the foliage, combines both a minimal contact surface with the air and the sun, and great aerodynamics, thus greatly limiting drying out.
The shape of the flowering: this spherical inflorescence, perched at the top of a floral stem which can measure from 40cm to 200cm, swings in the wind and allows the leek to propagate its seeds in the nearby surroundings, to be associated with its perennial life cycle, it’s sometimes forming large colonies.
And associates with its protandrous sexuality, favoring cross-pollination, this has the effect of accelerating the adaptation of plants.
The leek has a large root system compared to its aerial parts. This root system composed of thick white rootlets allows for the storage of water and nutrients.
They live in places that are systematically poor in nutrients, and sometimes even poor in soil.
And if we observe, all the material generated by the leek is intended to remain on site for the cloves of the following season: the leaves do not fly away, but dry out on site, protecting the cloves from the sun, and have a rapid degradation when autumn arrives.
There is no production of fruits, intended to attract mammals, the seeds do not fall much further than the amplitude of the stem (2m maximum) and when it comes to the seaside, the sea spray mostly ends up pushing the flower stems in the direction away from the sea, and therefore towards the land or higher than the mother plant if it is a slope.
…And I haven’t mentioned the role of its scabrous leaves against mammals; nor its content of essential oils and sulfur compounds, which have an inhibitory effect on bacteria, and which also repels certain insects and mammals.
From the very high salt resistance of Allium commutatum,
… Nor of their variable chromosome number, whether at the intra-specific or inter-specific level. Producing variable sexual compatibilities between the different species of leeks (which are numerous).
For example, several species of leeks that are partially or totally interfertile grow side by side on the shores of the Mediterranean: Allium ampeloprasum, A. atroviolaceum, A. commutatum.
It is little known that two species of leeks are cultivated and inter-fertile: A. ampeloprasum, from wild A. ampeloprasum in Europe, and A. iranicum, from the domestication of A. atroviolaceum in the Middle East, cultivated for its leaves eaten raw, its cloves, and its seeds eaten sprouted.
(It’s a somewhat crude text but it allowed me to state all the points.)
Now you have the keys to understanding the leek
But I don’t think microbial life has much to do with it. Besides, they often live in places that are hostile to life, including microorganisms.
For the production of bulbils in the inflorescence in case of sterility, yes, it is exactly the same case as A. xproliferum. In leek several examples exist, among them there are var. Babingtonii and a particular leek from the island of Yeu, Vendée, France.
But in the case of your bulbils, with preservation of sexual function, you will have to wait a few more blooms to know if they are systematically present. But the most likely is that it is a malformation linked to the unfavorable weather/environment and harmful to flowering, as I told you in the previous answer.
About the rust resistance of wild leeks. Now you understand why it is low, and that in a garden, in good soil (for them) and in an environment more humid than their natural environment; within a large number of plants of their species or other Allium species as is the case in my collection, diseases can destroy them.
In the domestication of leeks, increasing resistance to diseases and cold have been, (along with yield of course), the main selection issues. Rust resistance remains the main thing even today.