We do more things, and have more complex graphics. Eg, a 320x200x8 display has 64000 bytes of memory. A 4Kx32 bit display has 33177600 bytes of memory. That's

We do more things, and have more complex graphics. Eg, a 320x200x8 display has 64000 bytes of memory. A 4Kx32 bit display has 33177600 bytes of memory. That's 518 more times memory used just for a single screen. Take into account that these days we have compositors and each window is present in memory on its own, before it's composed into the result, and it's even worse. We also work on far bigger projects. The project I work on as a hobby has 400K lines of C++. Imagine the amount of processing an IDE needs to do to parse all of that and provide its various convenient functions. And of course a good chunk of that is in RAM, because that's far too much stuff to parse everything every time. Old tools also don't really cut it anymore. If I try running ctags on it, it comes up with a 14GB tags file. I don't think it handles it quite right.