Both steel and welded frames have finite fatigue lives, but depends partly on how good the welding is, but mostly on how stressed it is.
Also have a Specialized Allez from 2009 ish. It has done me stirling service over commuting and long distance rides, and is still in one piece. Unlike this one:
My old Peugeot failed at exactly the same spot after about 7k miles of my ownership. At the time I put it down to me being heavy and mistreating it but I've seen a couple of steel frames fail the same way and now think that there was probably a stress riser at the bridge which caused it.