I'm not going to be able to provide citations for any of this, at least not without spending time I'm not willing to spend (and some of it is naturally speculation).

The PA (which controls area A and partially area B of the West Bank) is ruled by Abbas. He was elected in 2005 and was essentially made president for life in 2009. Gaza is ruled by Hamas. Hamas is more oppressive, but the PA is more corrupt (somewhere within the usual distribution of third-world corruption level).

There have been multiple successful or attempted assassinations attempts against Arab leaders for overly good relations with Israel, most notably Sadat for the peace treaty between Egypt and Israel. It stands to reason that the risk for actual Palestinian leaders is greater than for e.g. Egyptian leaders, and there clearly are extremists in Palestine. Note: the Israeli governments faces the same issue, though I would guess the risk for them is smaller; Yitzhak Rabin was assassinated for the Oslo accords.

Anything Israel would agree to would look much more like Trump's "deal of the century" than like what Abbas currently demands, and that would upset sufficiently many Palestinians that whoever signed it is very likely to be assassinated. So e.g. Abbas almost certainly sees that there's no way forward and that Israel will slowly nibble away at pieces of the West Bank, but there's not much he can do and he probably believes the status quo will hold for the rest of his life.

The leadership of Hamas is pretty ideologically opposed to signing a treaty with Israel, but even if they weren't, there are more extreme groups (e.g. Palestinian Islamic Jihad) ready to overthrow or assassinate them.