I can see why they're replacing Counter-Strike Global Offensive with Counter-Strike 2 - to not split the community across games again - but with no mention of custom content, I'm worried that all of the Source 1 maps, textures and models are just going to stop working unless their authors port them over.
Counter-Strike Global Offensive came out 11 years ago - I don't think releasing the engine update as new game altogether would be the worst thing in the world.