There was never a place called Palestine outside of the British mandate

And there wasn't a place called the United States of America until 1776?

Only after ‘67 were these locations earmarked as “Palestinian land”.

Because Israel took over more land that was fully inhabited by the Palestinians (for the second time)

And why, when Egypt and Jordan made peace with Israel, did they renounce any claims to Gaza and the West Bank instead of pushing for Palestinian statehood in those areas? It’s almost as if the Arab world chooses to keep the Palestinians poor and stateless as a means to vilify and discredit Israel…

Assuming you're arguing in good faith, which is a huge assumption, the answer comes down to negotiating power. Egypt was able to get the entire Sinai peninsula back during these negotiations. Israel never fully gave up the Gaza strip, hence the second part of my tl;dr above: "Palestinians want their land back. Ensue 80 years of complications"