According to Wikipedia Cat5e became the common ethernet cable around 2001, it's still in common use and capable of carrying gigabit, or over short distances even 10Gbit ethernet. Today at least in my bubble I see Cat6 and Cat7 deployed instead for 10Gbit and beyond.

I think everyone is getting at least 20 years out of their Ethernet connections, likely more. That's not as durable as electical cables but good enough for most cases (plenty of things need updates after 20 years in a building).

You can tie a new generation of wire to your existing wire in the wall already and pull the new wire through end to end that way to upgrade your connections behind the walls.