Yeah, a big problem with the traditional PHP-in-HTML approach to generating web sites is that it's one of the areas where PHP hasn't dramatically improved since the early days. Later templating engines learned from the problems people encountered with PHP and were built to be aware of the output format, and PHP never did that. A lot of work was put into writing templating engines in PHP that in retrospect really should have instead been a language mode for PHP itself.

We would have seen dramatically fewer bugs and injection attacks over the years if PHP had made <input value="<?=$value?>"> a perfectly safe and normal thing to write back in 2005.

There are actually shockingly few context-sensitive templating languages for php and those that exist don't seem that popular (Latte is the main one I'm aware of). Most of them are more of the giant string concatenation type, maybe with escape by default semantics (e.g. Smarty, Mustache).