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The same could be said of any language. Most dynamic languages are roughly equivalent in the amount of skills that it takes to use, so there's obviously more to developer pricing than the language itself.

A lot of modern languages that were touted as competitors for PHP no longer exist or never became as popular as expected, so if you value job security and don’t have the ambition to be a jack of all trades, you can just pick PHP and make sure you’re really good at that.

I don't think PHP needs "saving". PHP jobs pay less because of supply and demand. There's likely more PHP developers out there than any other language. Higher supply leads to lower salaries.

This isn't really a problem; this is one of the selling points of using PHP. PHP is a a great choice for small websites; but if you're planning on building a product or SaaS with it then it's likely not the best tool for the job. However; in those cases it's main advantage is likely that developers are cheap and abundant.

This is because of Wordpress. Wordpress work pays less than application development typically. Writing an application with Symfony or Laravel pays market rate for an equivalent dev in your ecosystem of choice (Rails, Django, whatever).

The newsletter is specifically about PHP.