As has been said many times, current day OW instruction is nothing like the OW course taken by many of us back in the 60s (or 50s). My course was three weeks long (night meetings and weekends) and people failed if they did not satisfactorily complete all requirements. Today you can get OW certified in a weekend. I've seen the difference it makes.
my scuba class in 1977 was a college semester. Today, people are not willing to make that commitment. And to run classes for anything like multiple weeks, the cost would end up being prohibitive to many.
That said, when I teach a private or semi-private class, I take more time, more dives and end up with extremely dialed in divers. This class is expensive but is a high quality, low volume class.
Group classes take 2 weekends and a day. I work hard to impart the academic knowledge needed AND create a reasonably competent diver.
Do I see a difference in these two approaches? Yes, of course. But very few people want to make the time and money commitment for the private/semi-private class. We live in an age of immediate gratification and our industry must be able to survive within that.