Jason Campbell - 9 years in the NFL is pretty successful.
That aside, as other have said, our issue is not at QB, our issue is that both our OLine and DLine have been terrible this year. Look no further than Nick Foles. The guy is a career backup, but in 2018 he looked like a starter behind a really good Philly OLine. Oh, and he won a SB. So yea. A QB who can succeed behind a crap line is a LOT harder to find than an OLine that makes an average QB look good.