Pretty much anyone who has achieved "legend" status is overrated. There are countless "unknown" musicians who play better and sing better than the legends. The Legends have put together a package that puts their music across in a way that reaches many (but by no means all) people. Each of us is free to assign our own suckability rating to them, as you have done BBS.
Side note on JT. I, too, have never been a fan, but found myself at a JT/Carole King concert recently. I still do not like JT any better, and it would not occur to me to put on a Carole King record, but I must admit, I thought their show was great.