Because ‘high end’ boards don’t usually offer much more utility than mid-tier boards unless you’re doing serious overclocking, and basically no one does that anymore.
Tech has matured enough that even low-tier boards have enough VRM stability to do the minor tweaking 99.xx% of overclockers do.
And also, boards have become insanely expensive.
High-end motherboards aren’t selling…
Source: Overclocking.com
https://search.app/2jzhV3FjUWr5GRTB7