The one student who got caught for plagiarism when I was a TA was busted by turnitin. Maybe the tool isn't perfect but it caught this student who had painstakingly replaced every single word in a copied paper with a synonym. I'm talking "perhaps the utility is not flawless, but the use of this utility allowed for the apprehension of a pupil who..." etc.
So it either only caught a single cheater among some unknown number, or only a single student cheated? Neither case seems to justify the expense and hassle of subjecting everybody to this process, not to mention everything else wrong with TurnItIn.
I'm always shocked at how much students will put in effort simply not to do an assignment given. I guess this is just part of what you will get when you attach cultural and economic worth to a set of hoops to jump through [even if the intent is to have institutions of knowledge, sadly I think many students just see it as a way to get economic stability].
Unrelated to the cheating part, if you don't see American colleges primarily as a path to economic stability, I think you are probably either rich that it doesn't matter or haven't seen the bottom 25% outcomes of college graduates who didn't treat it as a financial opportunity/investment and are struggling.
grammarly is pretty old, Not sure when it became available, but it was already pretty well established as a high quality writing assistant by ~2012.
It had various tools and heuristicsv to suggest different phrasings and better words that were pretty incredible if compared to anything else back then
I was surprised at the level of effort