Baggs
When I was doing EFL training, what 'native' English speakers actually say was stressed as more important than what 'native' English speakers should say.
Everybody does not say it, though. And to me, ‘there are’ really doesn’t sound like ‘thorough’.
I taught EFL overseas (CELTA qualified at the British Council) and since our students so often had to pass exams where correct versions were required, we stuck to those. Purely colloquial, everyday speech may well be a different matter, but from experience, most students do want to know what is officially correct. Dd found the same when teaching EFL in sundry countries.