I literally just said that. What I'm disputing is that these 7 Kings could have not existed and simply been wholecloth inventions. That is frankly implausible. I also dispute that they had no written records. There might have been plenty of records that gradually faded, but enough that it could be held in the societal memory from more or less clearly from one generation to the next, until some of it was Chinese whispers, etc, but the core facts remained about right. This was not a despotic and illiterate society where you could easily change the historical legends at will. It just wouldn't have worked.
My point is that it's easy for kings to be added or removed from the "official" list, especially when there is no one keeping an official list. So I agree that it wasn't completely invented, there were definitely some kings in Roman history in the 6th and 7th centuries. I'm also reasonably convinced by the historicity and dates associated with Tarquinius Superbus and possibly the kings just before him. What I'm not convinced by is the number of kings, or all their names, or when the first king started his reign.