Franco,
Take a look at this:

http://en.wikipedia.org/wiki/Tokaji

And this reference pretty much answers your other questions:

http://www.masters-of-wine.org/Resou...ePDF/Atkin.pdf

Reading them over and comparing them to what I know sounds similar.
They started with a must _capable_ of 13-15%; adding this dough to it
makes it quite sweet. As I see it the idea is actually for the wine to
'stick' on purpose. They leave this pulpy must alone for a day or two
and then put it into barrels once it's started fermenting.

As to how can it live this long, what could kill it? You have decent
alcohol and decent acidity; as long as you change the corks as needed
they seem to consider this normal; they expect a good bottle to last
lifetimes. They don't shoot for a light colored wine so that's not a
big deal to them.

Hungary isn't well known over here in the US as a high end wine
producer but believe me, they are. They were making this before the
French made Sauternes. The reference to 300 year old wines was from
that book I mentioned.

Joe