I think even the comparison of two identically specced bikes from the same manufacturer isn’t a valid one.
Your average Ti frame will have double butted main tubes and straight gauge rear stays.. This is just a cost measure, as butting just the main tubes requires less machine time etc than doing all of them but gives a bigger weight saving. The more you spend, the more they can take away, and the more they can manipulate tube shapes for stiffness or springiness.
Most (decent) steel frames will have all the tubes double or triple butted. It depends entirely on the cost and frame material, but there will be a world of difference between a £200 steel frame and a £800-1000 steel frame, along with a big difference in ride feel and a good pound in weight. The same applies with Ti.
You could compare cheap steel with expensive Ti and say “OMG WOW!” or start with some decent tubed steel and compare it with average-joe Ti find the difference not so great.
I still *want* a Ti frame, but after having a decent Columbus tubed steel frame, it would have to be really bloody good to be betterer.