That is your opinion, and you are welcome to it. I prefer to go with what it actually says, and which I just quoted: "Promoting the general welfare" seems like an awfully broad charter to me.
Indeed it would be unlimited.
It was a good thing that the actual powers to effectuate that mandate were specifically enumerated following the statement. If it were a broad mandate, it would have been unnecessary to enumerate the specific powers that congress had.
Merry Christmas