Why we don't (and shouldn't) use old PC cases anymore

Throughout the 90s and into the early 00s, we relied on the standard beige mid-tower PC case. There was only really one color and design. Some brands worked in different elements, but you could instantly recognize a PC case from this period. I'm a sucker for sleeper PC builds and those re-using old parts, like my sweet-looking Mac project build, but an old beige PC tower has been resigned to history for a few valid reasons. I'm talking airflow, incompatibility, and overall aesthetic.