https://www.hollywoodreporter.com/live-feed/could-big-bang-theory-modern-family-goldbergs-end-next-season-1107195

All three network comedies are heading into the final year of their multi-season renewal deals. In The Big Bang Theory's case, according to The Hollywood Reporter, "WBTV and CBS have had some conversations about potentially continuing the series beyond season 12, which would require signing the stars to new mega-deals to return to the comedy from Steve Molaro and showrunner Steve Holland, though a decision could be made post-upfronts."

I don't see BBT continuing as it is now. I can see the possibility of a spin off into a show about Raj or maybe one of the couples. I don't think Jim Parsons wants to be Sheldon for the rest of his life.