[English study] Adjective phrase - Kind of vs Kinds of

Language is changing, and English is not the exceptional as well. There is an example that people just use the expression like “kind of” in front of noun. This is expression is not the numeral case, so plural or singular all accepted. However, this trend is changing now, and it is required to use the right expression depend on the word ahead.

Generally people use to use for counting something limited with 'sort of' or 'type of' more than kind of. People just use 'type of' for emphasis of counting. For example,

(1) I like this kind of car. (O)

(2) I like these kind of cars. (O)

How come the second sentence is correct grammatically? As I said above, people have just like to use 'type of' for emphasis, so both of them could be correct. I meant they didn't care of using 'kind of' between these and cars. However, these days people are trying to use that for counting more than before. That means they try to fit between these and kind. Actually, it was a kind of exception.

Therefore, nowadays the third sentence is getting correct more than before, but if you like to use something to count, it's safer to use 'type of' or 'sort of'.

(3) I like these kinds of cars. (O)

I know this is not always correct, but I think it is much better to understand how the language is changing these days.