I think people overestimate 2000s desktop functionality. macOS's mail application is still the good old crap app that it was since its inception. Outlook Express, Windows Live Mail, and the Windows 8/8.1/10 mail apps are all terrible in their own ways. Thunderbird looks like a skinned version of a late 2000s mail client and works exactly like it. Search is quirky and unpractical, but in completely different ways Outlook's and Mail.app's are!
Just for fun, try installing an old OS in a virtual machine. Marvel at how fast the old OS runs at modern SSD speeds. Get frustrated at the random hangs, freezes, glitches, and plain bad behavior of the programs you know and love, because the slowness of computers at the time hid it all. 20 cores of unused CPU power, dozens of gigabytes of RAM laying at the ready, disk I/O hitting dozens of megabytes per second, but still loading screens everywhere.
I once tried to go back, for nostalgia's sake, just doing the things I do on an old OS for fun. The grass wasn't much greener back then, I just had lower standards.
I mean, it was common knowledge even back then that Outlook Express etc was far from the best email client. That's why people used alternatives, so much so that some of them were paid and yet had enough people buying them to remain in business - e.g. The Bat!
Just for fun, try installing an old OS in a virtual machine. Marvel at how fast the old OS runs at modern SSD speeds. Get frustrated at the random hangs, freezes, glitches, and plain bad behavior of the programs you know and love, because the slowness of computers at the time hid it all. 20 cores of unused CPU power, dozens of gigabytes of RAM laying at the ready, disk I/O hitting dozens of megabytes per second, but still loading screens everywhere.
I once tried to go back, for nostalgia's sake, just doing the things I do on an old OS for fun. The grass wasn't much greener back then, I just had lower standards.