Back in 2005, we ran the worlds largest hardcore porn site (kink) on JBoss 4, jgroups with multicast, EJB3 and we did all of this on 3 servers, but only needed one and used the rest of for redundancy on fully automated rolling deploys. They weren't even very special servers... just some Dell blades.
We had full transaction isolation and it just ran thousands of connections and transactions per second, gloriously, without any issues. We had a micro currency (kinks), first 1080p pay per minute live viewing, and a whole slew of happy customers with .gov/.mil email addresses.
Kids these days with their 'microservices'... psssschhhaaa...