Look at the quality of the sport, particularly at the collegiate level, in the 1950s vs. that of the 1970s. It absolutely changed the game. And I would point out that the recent changes have nothing to do with how the game, itself, is played.
1. I think my terminology is imprecise. I'm stumbling over the rhetoric of "changed the game," which is a mistake because "changing the game" is typically associated with great players. And we need to separate the changes that occur in college basketball in particular as opposed to simply the evolution of the game of basketball. There's a lot more three point shooting in college basketball today than 30 years ago. But there's a lot more in the NBA too, and in the international game, so that's not a change in college basketball.
2. Consider that you're trying to explain the difference between college basketball and pro basketball to someone who is familiar with the game but not the institutions. For virtually all of my life, that explanation would begin with the difference between professionals and amateurs. Sure, there were differences in shot clocks and three point line distance, but these were never the defining distinctions. You wouldn't start to explain the differences between the NBA and college by pointing to quarters versus halves, or even necessarily the quality of play. The main difference is that the players were amateurs who were playing for a school team in one case, and professional players in the other. That difference structured the relationship between the players with each other and the coaches, with the fans, with the source of excitement.
To confirm, let's try the exercise with other categories of hoops. The main difference between HS and college ball is that, prep schools excluded, high schools are drawing their talent from a local school district. Coaches can't just go out and recruit a new PF to fill a hole on the team (again, in most instances). Most people in the stands have a connection to the players -- either as classmates, children, or kids people have known from the community since they were children. I attended a game last year because the visiting team featured a kid who was on my son's select team when they were 7. That kid is playing DI ball now. It was interesting to see how he developed over those ten years. I saw him as a kid. I caught up a little with his dad, a former professional player who coached the team. It was a different experience.
[Incidentally, my son was amazing as a 7 year old and just as good as that kid. I had taught him a quick release, and he was an exceptional shooter -- he would regularly knock down 7 or 8 17 footers in a row off a catch or off the dribble. Nobody could guard him. Alas, that was my son's peak. After all, he has my genes. Also, my son turned out to be extremely injury prone and he's only 6'1", and was never going to commit hard to hoops because education is too important for us, but anyway I digress.]
And do the same with international basketball. Again, you wouldn't explain the difference between the games by pointing to the different shape of the key or the offensive goaltending rule. It's that the teams are composed of players from one country, and they are representing that country. It creates a different level of passion among the players and the fans. As with HS, teams generally can't plug holes on their roster by importing new talent. If you're the French coach, you have big men for years and your challenge is to find some guards; if you don't have the guards, you need to run your team through your big men and that determines your team. Smaller countries have even more of this.
And so going back to that question at the beginning: what is the difference between college basketball and pro basketball now? Nothing, really. College basketball is pro basketball with slightly different rules. That doesn't make the "college" game today worse than it was; maybe it makes it better (though I doubt it). But it does mean that it's fundamentally different than "college basketball" as we knew it.
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I'm having some trouble finding the words to express my thoughts. And that undercuts my confidence in my own position. I believe that most difficulties of expression are actually difficulties with concepts. A well-thought out idea is much easier to explain than a messy one-- well, that's true for me at least (probably true of most people but whatever). So I will admit that this discussion has revealed to me that my thoughts on this matter are perhaps more a matter of intuition than I had thought. Funny, that. It's almost like reasoned discussion can be illuminating.
At the same time, my intuition on this point is quite strong, by which I mean I keep coming back to it. When I try to formulate in my head the contrary view, that the college game is not fundamentally different than it was, it keeps crumbling. I think back to the recruitment of Jawad; back then, Bret Bearup posted on the uncbasketball boards for a little while. He was one of the player-empowerment advocates. I wrote eloquently about what would be lost if he had his way -- the involvement in the program from the fans, especially as it pertained to recruiting. At the time we were recruiting Jawad, and it was tense because we had already (fortunately!) missed on our first target (James White) and we got in late with Jawad. He had been a Maryland lean, and when it came time for his announcement, there was excitement and nerves. We were looking good; but if we missed on him, we weren't going to get anyone. Incidentally, Bret sent me a PM asking if I was interested in a job doing community outreach. LOL. I told him I was in law school and also that I would be shit at that job, message board posts not withstanding.