Exactly. Enough supports 10gbe that you might as well grab it; a few Mikrotik switches, some old enterprise gear, and an adapter gets you some good speeds.
Sure some of it might have been fine at 2.5 or 5 but those are relatively new and less commonly available.
I'm actually surprised at the amount of 2.5/5 gear I've been coming across lately, especially in the 2.5 space as more ISPs are pushing for gigabit+ to the house.
Verizon's been issuing a wireless router with 10G WAN and several 2.5G ports and MoCA support that includes a 2.5G adapter and they use that across all their current connection types. I was delighted to see that when I got the router a couple years ago.
10GbE can be extremely cheap now if you're doing things like buying Intel NICs off eBay to put into your own test/dev headless servers.
There is also a glut of 40 Gbps stuff on the market because it's a dead end technology and most ISPs went straight to 100 for things like aggregation switch to router links. Not that I would encourage anyone to go whole hog on 40 Gbps just because, but if you can get a transceiver for $15, NICs for $30, and maybe you get a switch for free from electronics recycling or for 80 bucks, and can tolerate its noise and heat output...
I have seen plenty of people throw decommissioned 40 Gbps stuff straight into electronics recycling bins.
Mellanox ConnectX-3 40 Gbps QSFP NICs are literally 20 bucks on ebay.
Sure some of it might have been fine at 2.5 or 5 but those are relatively new and less commonly available.