Maybe that’s part of it, but I’ve also noticed autocorrect on my devices often correcting incorrectly. As in, I type the word correctly and it decides “oh, surely you meant this other similarly spelled word” and changes it. Sometimes I don’t notice until after sending the message.

That defiantly has something to do with it

Having grown up around immigrants and other folks who learned English as a second language, I always attributed "loose" for being a signal that perhaps English isn't the writer's first language.

I think what you say is partly true too, but it's not a new phenomenon. Some examples

- awful used to mean "awe-inspiring" https://en.wiktionary.org/wiki/awful

- you used to be the plural/formal second person pronoun with thou being the informal form https://en.wikipedia.org/wiki/You

- prior to the printing press English didn't have any standardized spelling at all https://www.dictionary.com/articles/printing-press-frozen-sp...

Language evolves. The English we learned in grammar school is likely not going to be the same English our kids or grandkids learn. At the end of the day, written communication has a single purpose — to communicate. If I can understand what the author is trying to say, then the author achieved their goal. That being said, I wish my mom did use spell check or autocorrect because her messages often require a degree in linguistics to decipher, but because of typos, not spelling. Maybe she'll influence the next evolution in typed communication :)

Edit - formatting

Could also be non-native speakers .. Even as a former grammar nazi, now that English isn't my daily driver language I find myself making basic mistakes .. (two, too, to / its, it's / etc.)