Mac GPU isn't the bottleneck for most games. Compatibility is.

Just built a workstation with an older Threadripper Pro. It has 128 PCIE lanes, for 7 16-lane PCIE slots. An egpu has 4. I have one GPU, at x16, and I can add more.

Most people don't need that, but most people don't need an eGPU either. The number of gamers who would switch to Macbook+eGPU is negligible. It's just not compelling. For LLMs, hanging a 5090 off the thunderbolt port makes prompt processing fast, but I will be surprised if the M6 doesn't come with silicon just for that, as its the current gap. M5 is quite adequate for token generation for the price, given the RAM quantity and bandwidth. An M6 that accelerates TTFT would make an eGPU irrelevant.

For gaming, the threadripper gets at least +20FPS for windows vs linux, and some games just freeze for periods of time on linux with things like dynamic frame generation. I have an SSD for windows just for gaming.

I assume your reasons are different to mine so for your reasons it might very well be true. But for my reasons definitely not as long as Apple Silicon can't run Linux somewhat decently natively - and even then, it's still an Apple..