HEVC actually requires a $1 license you can get from the ms store. It’s a royalty thing. OEMs often ship PCs with that license already enabled.
There are more applications than just windows Media Player that won’t play hevc files/streams without that license installed.
VLC doesn’t really seem to care about those things though and it’s better than the default anyways.
Kinda the same thing as winrar. They rather have consumers get used to it so the companies they work at have a higher chance of buying licenses. That’s where the real money is.