Not gonna happen that soon, sorry. There's a few easy enough changes to improve PG connection scaling considerably, but to get to that count more invasive changes are needed.
It assuredly won't do very well, since it uses process-per-connection.
That said, it sounds like off-roading in a Corvette. You're gonna want to use PgBouncer or PgPool or something else altogether.
That'll be like CGI. Not scalable. You're supposed to use something like PgBouncer.
Look at the numbers for MySQL without the thread-pooling and that will probably be close enough.
PostgreSQL uses processes not threads which tend to be heavier.