Everybody knows it's wrong in the sense that Newton's theory is wrong, and that Einstein's theory is probably wrong. Models get refined in physics all the time,

Everybody knows it's wrong in the sense that Newton's theory is wrong, and that Einstein's theory is probably wrong. Models get refined in physics all the time, that's how it works. The BBT has a lot of issues in the details, but the overall picture - that around 14 billion years ago the universe was in a hot dense state and has been expanding ever since - is absolutely undisputed since Penzias' discovery. We can literally see the expansion, and we can even see the glimmer of that initial hot dense state. That's exactly the CMB discovered by the Penzias and Wilson.