As someone who deeply misses Python (warts and all) and due to a job change forced to take on PHP (thankfully, we are on an aggressive language versioning schedule, so we're already on latest 7.3) as the full time language of of choice, I miss a few things that just make me want to pull my hair out:

For what its worth: I used (and personally still use) Python 3.6+ so the comparison is with that.

1. Async programming. While in Python its not perfect, having it baked into the core of the language makes so many things trivial like processing jobs between requests and sending the results back later, or having a simple queue for persisting data to a database after validation has been done on the data (Marshmallow is my hero for this).

2. Not having to worry about all the strange things you have to worry about when everything has to be re-built per request. While I understand WSGI requests are definitely this (kind of, usually you have a daemonized runner that keeps your app alive even then), your entire app did not spin down between requests like it does with php. Simply having to rebuild everything every single time a request comes in (even when using php-fpm, more or less) drives me insane, because I can't just send some data off to another channel in memory easily, or sleep a generator in a position and resume it when I need to. Everything has to be handled in said request. This kind of goes along the same lines as number 1, but its sort of a different problem (in particular, I think generators in Python are very elegant in comparison to lots of other languages, not just PHP (looking at you javascript), but PHP generators feel worthless unless I'm reading something line by line from a file or some other external resource, or I'm iterating against say, a doctrine array result)

3. Your app is full stop dead without a cache if you are planning on doing anything interesting. I don't just mean like opcache, but even small applications have to leverage this (APCU at a minimum), because of the aforementioned problem of nothing being alive after a request has been spun down. Yes, I have leveraged caching before, and yes I leveraged it all the time with python, but for just getting a quick prototype feature out the door, and adding those kind of layers later, I really miss that. Try iterating through database results non-sequentially, where you have tons of variable conditions on how that data needs to be shown, its a pain in the ass without caching aggressively (this is unfortunately a very real scenario I have to deal with all the time. We have non linear questionnaires in my current job I have to deal with, and the questions have to pass a certain validation and then we either have to get the next immediate result, or skip `x` ahead, without really knowing whats what or having any real idea of what anything may be keyed to. I'm open to suggestions if anyone has a good link or something to read on this kind of problem. I have not found it easy to work through personally with php)

With all that, Its been an OK experience though. Not my favorite language (may never be). However, if I was to postulate further, if PHP doesn't start gaining traction on these issues (and no, the weird async extensions are not a replacement for any of this. It needs to be core to PHP and maintained as such, for it to work in the language, in my not so humble opinion), it will eventually be supplanted in full even where it may have some strengths.

Unfortunately, nobody working on the core of the language seems to care about this at all.