For Abbas to make a declaration that essentially forfeited the rights of millions of refugees, he'd have to be have an ironclad guarantee of a free, independent state that very day. And of course there's absolutely no reason to assume that making such a declaration would result in Israelis suddenly electing a non-extremist government. Besides which, the refugees outside the WB and Gaza never voted for Abbas and thus, he doesn't have any legitimate right to forfeit their rights. They could just as easily reject his authority and form their own organization focused not on creating a Palestinian state but on returning to their own homeland, and nobody could fault them for doing so. The fact is, the two state solution's only chance is in the UN and by increasing diplomatic pressure on Israel. If that fails, then it's one apartheid state in which Jews will soon be the minority.
Police disperse hundreds in brawl in Kafr Manda, northern Israel (Haaretz)
from the article: Open letter to Mahmoud Abbas for Yom Kippur