Isn't there also the global decline of english quality because of it being broadly used on internet by non native speakers? Many people (including me) get influenced by what they read on the net, to the point of accepting some of the strange forms you describe further down. There's also a global lack of proofreading all across the web, people editing content through web interfaces, on devices not supporting even simple spellchecking. English on the multicultural web is a strange melting pot of english forms and foreign ones being shoehorned in english. How much is (the)[1] american english influenced by spanish for instance, given the growing incidence of the spanish speaking population for the last few decades?

[1] Here I'm not even sure if I need to use "the" there. In my native language I would have to use it, but isn't the expression "american english" specific enough to avoid the need of it?