Adding new features doesn't help that. Only gradually deprecating old ones (or waiting a few decades) does, and that doesn't seem to be in PHP's blood.
This creates an echo-chamber-like environment that's not favorable to the evolution of a rich programming language. Since they never got to learn other languages (at least not enough) its evolution is guided by partial impressions of what other languages offer. It then becomes a collage of partial implementation of concepts similar to what other languages are based on.
Try explaining recursion to someone who only knows 8-bit BASIC (where all variables are global and functions are implemented as subroutines with known input and output variables). It won't work.
I've met more than enough PHP programmers who genuinely tout "it's free" and "you don't have to declare types" as unique advantages, or are unaware that you can even build a website in anything else.
Have you even read a PHP changelog recently?
You're suggesting self-proclaimed radical changes but not giving any information about the actual advantages?
In Perl, variable declaration was originally even worse than it is in PHP: any variable, anywhere, required no declaration and was assumed to be a global. (This was inherited from... some combination of awk and shell, I guess.) Obvious problems aside, a practical implication was that recursion was pretty awkward, since the callee and the caller were sharing the same namespace for the same code.
Perl 5.000 introduced the `my` function, which would declare a variable as lexically scoped. This solved the practical issues, but it left the problem of error-checking: a typo in a variable name would still create an implicit global with no warning. The solution was the opt-in `use strict;` declaration, which disabled the implicit-global behavior and made unrecognized variable names a compile-time error. Code could be fixed and then opt into the stricter semantics on a per-file (or even per-block!) basis, and nowadays most Perl devs will jump on you like a pack of hyenas if your code doesn't start with `use strict;` or some equivalent. Over time other features with too-sharp edges have been culled, still supported by the interpreter (Perl is more or less compatible going back decades) but made illegal in strict mode.
JavaScript's weird "use strict" opt-in is a spiritual port of Perl's approach, stuffed into a string literal to fit into the existing syntax. One of its effects is even the same: assigning to an unrecognized name is now illegal, rather than creating an implicit global.
I'm not aware of anything so fundamental being changed in such a heavy-handed way in PHP. From the outside looking in, I'm not even sure the PHP community has a strong consensus on what PHP-specific features to avoid. I'd be happy to learn that I'm wrong on either count.
i can't think of things that actually come up like that in php these days - things like register globals and magic quotes are long gone..
Undeclared variables in PHP produce an E_NOTICE, right? Better than Perl 4, at least. :)