It's possible I'm just less adventurous now.

Nvme drives just plug in on mobo and take zero space. I don't have to navigate and bend and fit massive ribbon AND power cables from one end of case to another. 3-4 Nvme fit onto mobo basically invisibly. Want more - cheap easy riser card.

3-4 3.5" PATA drives with ribbon AND power were just fun times / exercises in masochism! And of course different types of ribbon cables, and pins on hard drive begging to be bent, and master / slave hardware settings, and some cables could burn things if plugged in the wrong way around and you had to pay attention that red line on cable aligned with tiny pin 1 on drive. And after a while or if you bend it too much that ribbon cable will give you fun intermittent errors.

Power supplies came with random assortment of built in cables you had to tuck whether you used them or nit. Now you pick and plug in cables you need.

Separate audio card and modem and network card, so definitely had to worry if I had enough Isa slots etc. Now mobo does it all. Maybe even a worthwhile integrated gpu - my 8845hs with 780m does ridiculous amount of gaming. Compared to a 2d card PLUS a 3d card and pass through cables between them - did we forget about those?? :-)

Absolutely did have to worry if my after market cpu cooler will fit back then. Perhaps with stock coolers ones we didn't but I think same is case today.

And I'm just not ready to accept the argument that thermal paste or BIOS were somehow better in 2001 without some solid evidence :-).