While I agree with shot clocks being good for the game, I find this quote to be misleading. A pro thinking over 30 seconds is almost never them not having any ideas of what they could do, but rather them spending extra time trying to pick the best option out of everything available. Perhaps they are increasing their odds of winning the safety exchange from 60% to 65%, or running out from 98% to 99% on average by spending extra time weighting out different intricacies of the possible cue ball paths/error margins and whatnot. All the pros will see the different ideas very fast, some just make their final decision faster, whereas some prefer to gain those tiny advantages from more optimal shot selection.
Then there's those who spend longer due to nerves/composure issues, which I definitely think everyone should try their best to not let affect their speed of play.
Some pros might even be deliberately slowing their pace down at critical moments, or in general, to mess with their opponents rhythm.
None of these reasons are about being incapable of coming up with ideas of something to do.
At amateur level, it happens though. A lack of experience leads to slow shot selection and shot routines, but those aren't relevant for high level tournament shot clock regulations.
This is a generally well-reasoned and well-presented post, offering the intuitive, but ultimately irreconcilable-with-experience, argument that slower play leads to better decisions and better play.
In fact, I would suggest that two of the most "celebrated" slow players of recent times make better decisions when they play on the shot clock. That would be BCA Hall of Famer Ralf Souquet, widely regarded as one of the slowest players of his generation and potential BCA Hall of Famer Eklent Kaci, widely regarded as on one the slowest of this generation. As superstars, each has always had to play the late rounds of major events with the shot clock, and each has produced his finest pool with the shot clock in use. Neither of them ever showed any signs of slippage when forced to play faster, but when they were permitted to slow down in matches without a shot clock, they played very slowly.
Neither Souquet nor Kaci held the game up because they took an eternity to decide what to do, but instead because their processes of setup, pre-shot-routine and shot execution took longer than that of others. This is why members of this forum have so often labeled them as "unwatchable" in matches without a shot clock.
The shot clock abusers, who take the full thirty seconds on almost every shot and take forever in matches not having a shot clock, for the most past, are often not slow decision makers at all, just slow players. Some wipe their cue down on almost every shot, some go to their water bottle on almost every shot, and some have other time-consuming habits that are unrelated to decision making.
So, while it would be logical to assume that slow players are using the extra time in decision making and that their lethargic ways are leading to better decisions and better play, I have not seen any evidence of it in my 48+ years around pro pool.
I would, of course, agree that players will make better choices if given thirty seconds than if given fifteen seconds, but I have not seen evidence that turning off the 30-second shot clock in a match produces a higher level of either conceptualization or execution. I agree with Bob Jewett that the occasional shot requires a little extra analysis, but that's what extensions are for, and, including the automatic extension on the shot after the break, one gets two extensions per rack. That's more than enough for me.