I recall using a business desktop back in the day with a common IDE disk, and also attached to a NetWare share. The NetWare share was much faster than the local drive although the network was only 10BASE-T. Around that time meetings began: how much was it going to cost to replace all the cable (half of which was still coax) and buy 100BASE-T switches? (Answer: a couple hundred dollars per drop.) That process took two years and another six months to do the work: a quarter of a decade.
1000BASE-T was specified for Cat 5: the floorboards didn't have to be torn up to replace all that cable everyone just paid for. The cost of PHY/SERDES components fell greatly during that time and made 1000BASE-T hardware affordable. Moving from 100BASE-T to 1000BASE-T was, therefore, cheap and easy and took correspondingly less time.
When we had hard drives that barely topped 1 GB, which could be copied in under 17 minutes even on 10 Mbps, there just wasn't a huge incentive to upgrade speed. But once 100 made sense for homes - supporting 802.11g - the price of switches fell rapidly because it was no longer just businesses buying them. And so 1 Gbps fell more quickly, because the background hardware was getting cheaper.
My 1998 computer with 100 Mbps and a 6.4 GB drive got used a few times as the piracy data exfiltration machine because it could pull down the 5 GB of stuff we'd accumulated so much faster, then plug it up to the three-apartment network we had set up and let everyone pull it to their own machines on the 10 Mbps we had there. Our outgoing connection was a Linux box on a 56k connection shared among six of us; it's not like 10 Mbps slowed any of that down.
Unless you are copying large media files around all day, gigabit is complete overkill for the vast majority of people.