When I said plan for success I didn't mean PHP can't scale it was related to the lower argument that very few people under 25 uses PHP anymore.

(In truth the benchmarks I've seen show PHP is faster than modern languages)

The point is from a management perspective being able to hire cheap junior programmers is a significant issue. Finding someone young, cheap and experiences in PHP is hard. Even harder if you want the people you hire to be passionate about their job (using yesterday's technology makes you seem like a dinosaur to many)

Trust me I've been on the other side of this. I, to this day, believe 80% of startups would be better off using ASP.NET MVC. But if I were building a startup I wouldn't pick that as my platform. Because the most talented young developers don't want to work with Microsoft technology.

Honestly I'm not even going to bother with your last argument. If being clear cut could automatically cause everyone to agree we wouldn't have political parties, religions and any host of other organizations based around disagreement.