Extended fermentation

When it is claimed that chilies or vegetables get fermented for months or even years (like Tobasco) I am confused, as to my knowledge, fermentation will only prevail until the sugars are consumed, which will happen is just a few days or weeks. Even if sugar is added the rising alcohol level will inevitably kill the yeast and the process should come to an end after a relatively short while and the alcohol will turn into vinegar if exposed to oxygen.
Please help. I will appreciate an educated scientific based answer. No guessing or urban beliefs.

I think you answered the question, but discounted it at the same time. If you want to store it longer, do not let air in. I can store my wine a long time, i just keep the air lock attached.

Thanks for the reply but I'm not talking about storing or aging the fermented substance, I'm referring to the  very long periods of time, like sometimes years, claimed for fermentation processes in recipes, which to my mind, is not possible. And that when they're talking about vegetables or chilies, which unlike grapes, have very little sugar in it.
I suspect that they're confusing the curing (aging) period with the actual fermentation.  

Welcome Peter. I am an active domestic fermenter with a background in chemical engineering. I recently purchased "The Noma Guide to Fermentation". The book is fantastic.

There is very solid information on the fundamentals and even more on techniques that can be used to replicate the ancient methods.

Miso for example is a long process. let me quote;

Miso is a fermented paste made from a mash of cooked soybeans, koji and salt. Like vinegar, miso is a two-stage fermentation. First the fungus Aspergillus oryzae is grown on either rice or barley to produce koji (read the koji chapter page 211) for a deeper understanding of this process). Then the powerful enzymes produced by koji, namely protease and amylase, are harnessed to dismantle the protein and starch in another substrate (traditionally soybeans), cleaving them into amino acids and simple sugars, respectively. Wild yeast, lactic acid bacteria and acetic acid bacteria also add to the fugue of flavours as the miso ages.

I think this quote answers your question.

Druce

Thanks a lot.

What we call 'aging' is actually a microbial fermentation, esp from a historical non-sterile perspective.
There is instead other microbes that is using up the oxygen that slowly dissolve overtime in the previous fermentation step. Some are digesting/fermenting microbial biomass from the previous fermentation step.

Lactic Acid/Ethanol/Vinegar aren't the only compounds created my fermentation microbes, vitamins, solvents, numerous organic acids, esters, short chain fatty acids, digestive enzymes, etc. These compound reacts, off-gas, precipitate or are eaten by other microbes.