You only need 65k STEEM to bring SBD price up to one dollar. why instead of this useless project, those behind this experiment creat a fund to keep buy orders of 1 USD on the exchanges, then burn the sbd bought?

This exactly what they're doing. They are buying the SBD on internal market and there are bots that make sure that the SBD price on internal market and other exchanges is the same (because there is profit to be made if price is not the same). Then they are "burning" the SBD by converting it to STEEM, those converted SBDs will never hit exchanges again.

There will always be steem/sbd entering the system.

The only SBDs printed are going to @steem.dao and small part of it to few project creators.

Basically what @sbdpotato is doing is limiting the supply of SBDs while creating constant demand for it.

You know what could bring real value (and bring the price up)? Support to projects like @utopian-io, killed by the price drop, but the big whales (not all) didn't gave a shit when it died.

Throwing money to projects that are not self-sustainable won't make them sustainable. Look at steem monsters, they don't need any donations and the steem price have no effect on their success.