I use php for my startup and all new things are made in php for these reasons.

the ecosystem is very much complete. There is nothing that has not been done and tested in php.

Plenty of developers know php and if you have done C#/Java/C++ etc its super easy to learn.

Its easy to setup and well documented and the LAMP/LEMP stack is battle tested and people know it well.

There is great Editor/IDE support with plenty of options to choose from.

You can run it on any kind of developer-os and do you development there then just deploy it to a linux server. Altho docker solves this now with any lang its still nice if you dont want to use solutions like this. I have devs developing on windows, linux and mac with no issues getting the whole development stack running and then deploy the app on linux with no issue. This has been a challange in ruby on rails last time i tired it (back in 2010).

The laravel framework is great.