agreed. I was visiting Bucharest last November and was surprised that there were multiple tech meetups on meetup.com. Perhaps I shouldn't have been, but ... I was just... pleasantly surprised. I wasn't there for work, but found a couple evenings where I ended up having the night to myself and stumbled on the idea of checking my meetup app and... bam - multiple places to go meet up with tech folks. More than I had time for actually...
Bucharest is capital, not 'just' an EU city, but it's by no means the largest nor would I think it has the most tech folks compared to other areas. (maybe that's wrong assumption though?)
Healthy ecosystem exists even in rather small cities. Up here in Vilnius, Lithuania, small-sized backwater EU city, we've quite a few meetups with a decent amount of networking opportunities. Sure it's not as SV scale. But even < 1million metro area can sustain that.