Probably but you can still have the configuration secure as default and people would be aware of the security implications when enabling insecure features.
I am talking about whoever is packaging PHP for the OS, there is a default php.ini that comes with PHP on CentOS is insecure by default (I can't remember off the top of my head which settings were set to something insecure).
We are talking about an ini file. This isn't rocket science.
Right, but they need to be conscious of their end user. If they secure by default, and someone upgrades, their software stops working. Should PHP have had these defaults to begin with, yes absolutely. But now we're all stuck with a million miles of code that will break if register_globals is turned off. That's the point. Everything you've stated above there might as well be an alien language to the majority of people using this stuff.
No it should be secure by default and people will have to enable insecure features. It doesn't stop old software from working as the person will be able to simply re-enable whatever the insecure feature is.
However they will now be aware that said feature is insecure and should know the consequences of enabling it.