PostGIS. pgvector. TimescaleDB. Citus. pg_cron. pgmq. Apache AGE. ParadeDB. hstore. plv8. postgres_fdw. pg_partman. pg_stat_statements...
The extension API is the thing making your thesis possible. Rewriting it away would mean deleting the exact feature you're asking for.
I won't be running that, though.
pgrust.
As to the age statement, why on earth does that matter? HAProxy launched in 2001, and despite it being 25 years old, you’ll struggle to find anything faster or more stable in its field. Then there’s, you know, Linux - 1991. I suppose you want to see it rewritten?
This is a pretty poor take. Sure the software that we call "PostgreSQL" started to be developed in the 80's... but they didn't stop there. PostgreSQL has been in continuous development, including improvements, changes, and additions, and by some very smart people at that. It's not static and as long as I've been a professional user of the database, decades, it has continually evolved and in some cases even led the way. If we were to survey the software, wouldn't you at least be interested to know how much of code base actually dates back to those long ago decades and how much is more modern before making such statement?
It would be a mistake to take what PostgreSQL actually offers: an excellent database that has be continuously developed and updated over many years (i.e. "maturity"), for some arbitrary idea and evidently baseless idea that somehow "new" must be better.
If new is better, say why; and do so with more actually true statements than it's not extensible. Want it in rust? Well, OK, sure you can give hand-wavy reasons about security and such for why that might be beneficial; but if you want to be convincing you need to be much more specific about the problem in PostgreSQL and the specific way in which your recommendation actually and convincingly moves the needle. If you can't do that, you're simply giving us an emotional outpouring rather than a rational one.
I would propose a rewrite of Postgres in another language like Rust, introducing a pluggable application layer on top. While ambitious in scope I think it would be helpful and even necessary.