Ya acrylic side cases where a trend, maybe 3D monitors but everything else in there was just specific technology that has been replaced by better technology..
Blower fans had a technical reason to exist that isn’t very relevant anymore.
It used to be to keep the card profile low so you could have other PCI card slots populated. However these days everything including Wifi can be found pre populated on the motherboard. It is rare you put in any additional PCI cards in modern personal systems.
ATX boards had most relevant slots below that already, especially due to SLI / CF being a thing at that time. I know because I used wlan and audio cards back then - that is with the third party cooler + fans, which blocked like 3 slots.