If I have 999,999,999 gil now and decide to buy something for 30mil (double melded obelisk as an example), I would only be spending about 3% of my gil. When 2.0 comes around and my max gil is reduced to 99,999,999 and I still see the same item selling for 30mil, I just won't bite because I'll be losing 30% of my income. That said, if I had a double melded obelisk in 2.0 I would probably sell it around 5-10mil because some fool might think of it as a steal and splurge not realizing he lost 5-10% of his income. Moral of the story? Adapt or be prepared of people taking advantage of your stupidity.
