Your comment is not entirely wrong. The reality is the $130B is left because people were too scarred to touch it after the government threatened to criminally prosecute companies after public outrage of large public companies obtaining loans. The public outrage was driven, in part, by the fact that lots of small businesses didn’t get loans before funds ran out the first round. That’s not a sign that there were adequate funds.

There are estimates that we actually need a second PPP of the same size ($600B) because lock downs are going to start again.

You're not actually wrong, to be fair.

They allocated 350bn, it all got spent.

Then they allocated more, and some of that second round of money is left.