35 years later, burner phones regularly come with 4 GB of RAM these days. 3 order of magnitude difference, not taking into account miniaturization and speed improvements.
In another 35 years who knows what will happen. Yeah things can't improve at the same pace forever but I would be surprised if anyone back in 1990 could predict the level of technology you can get at every corner store today.
Maybe it's not that everyone gets an RTX 5090 in our pocket, but maybe it's that LLMs now can run on rpi. Realistically it's probably something in the middle.
Phones with 4gb ram is not feasible today because they wouldnt be able to run Android and phone home comfortably, even being a thin client requires running Android and react application on electron. 4gb is not good.
In 2040 phones will came out with the bare minimum to run Android, all the stupid Chinese apps Android distro pushes into consumers, and a react application on electron.