I think it's you who's overrating Romario. I guess you watched him when you were a small child, and as we all do, you highly overrate the players from your beginnings as a football fan. I do the same with the stars from the late 80's.
Romario was without a doubt a deadly striker. In 1992-1994 he was probably the best attacker in the world. But eventhough he wasn't injured or something, his time (as someone who consistently performs well at the highest stage, not some Brazilian leagues) was rather short. The spotlight of his career was the 1994 WC and people mostly remember him from there.
As someone who followed him and even loved him a lot, i must disagree with you. Only in the last 2 decades i think that Van Basten, Ronaldo, Henry, Batistuta and maybe few more that i can't remember right now were all better than him.
Del Piero wasn't inferior to him also. Maybe Ale didn't have 2-3 great years in a row like Romario, but overall he's not inferior to him.