MCU will live on for years but it's not going to be like it was before Endgame, which was too much of a conclusion to keep hype going. Hopefully Disney doesn't expect literally who Shang-Chi or the Eternals to gross billions.
They have yet to put out a bad outing (they do have quite a few average ones). If they keep up the quality, they can go on for quite a time. Especially with the wealth of source material