[nisa]

    Compatible up to: 3.4.2
    Last Updated: 2 years ago
    Active Installs: 400+

WordPress 4.5 is current. Anyone doing WordPress will just skip this if they don't have developers that can fix the issues. Also while the base may work a lot of popular plugins (used to?) don't utilize WP_Query or whatever else WordPress offers.

It's also probably easier to add indexes to the code or rewrite the logic. Mostly it's bad database code that sucks on MySQL and would likely suck the same way on PostgreSQL.

Besides that if you use an object cache like memcache or redis you can avoid a lot of database accesses and InnoDB seems to be able to deal with concurrent tables like wp_comment.

Would be cool to see in WordPress itself but I doubt it.