That's very interesting. I have noticed a high resistance to dewormers here by BYCers, rather than by the worms, lol. I don’t understand the reticence to use medication when necessary. Here in the UK, we don't try and identify which worm it is, we just treat with a dewormer because it kills all the worms. I buy over the counter, but if that didn't work after a couple of treatments, then I'd consult my vet.
I've never floated faeces!!!
Luckily I have never had a worm problem that persisted beyond normal meds. I also use Vermex as a preventative and it does fine.
Best of luck to you. I do like a bit of science myself!