Well, HP's new version of the Reverb jumped to a 2160x2160 per-eye resolution.

If Pimax can get their shit together, the 4K resolution and ridiculous FOV is promising.

I think the ultimate problem is that the higher-end market isn't willing to spend what it would require to build a sufficiently-good headset right now, nor are there many home gaming computers that can realistically pump 8+K low latency, high FPS graphics. There are many millions of people who might spend $500 on a standalone headset that is good enough to play beat saber, though.