3.7L: Main bearings a common issue?

[KJDevildog]

Been researching the thump sound I hear coming from my engine, and from what I've read about bad main bearings, this is exactly what mine sounds like.

For an engine with 94000 could this be a common problem? How bad would it be to drive the Jeep if this is what is happening? Something that needs to be replaced ASAP?

Thanks!