There are certain attributes that cannot be learned, as they have as much to do with not only a persons physical build but it also relates to how our muscles elongate thru repetitive motion, i.e. as we grow, the sport or sports we participate in develops our muscles in certain ways. During a persons growing stages, if you decide to be a bowler, your muscles thru the act of delivering a bowling ball, will elongate along certain lines in your body as compared to the golf swing, which is more rotational. This is why as we get older, it becomes difficult to evolve into what younger athletes are able to do. There is much emphasis these days placed on core strength along with increasing range of motion, in certain areas thru yoga & stretching, but at a certain point, an athletes bodies is what it is...the reference teaching an old new tricks come to mind.
From watching the video it does appear your rev rate & speed match up fairly well. I'm not sure what professional instructors you're referencing (as I would fall into that category) but there are only certain variables that influence swing speed, a person's build is the primary. You're only going to create a certain amount of ball speed naturally, going beyond will tend to become muscle which tends to eliminate consistency & accuracy. Length of arc, foot speed and length of arm all go into the equation but we all have a certain rhythm and tempo that is a persons own identity.
Also in today's modern game, more emphasis is placed on having the proper piece of equipment, with the proper surface, in your hands ,at the proper time and also in the correct part of the lane...if you're not, you are sacrificing pin carry. Also the type of game you possess is what dictates the types of conditions you'll score on, in comparison to conditions you're not getting bird dogs on...there are certain conditions that it may just be using the wrong ball on, as well as too much ball speed can create the incorrect deflection at the pins decreasing pin carry.
I applaud you're desire to improve, but as stated previously and as it is can be proven, at a certain point in aging, our physical attributes are what they are & unfortunately cannot be changed. There are reasons why certain players dominate on certain conditions...they possess something no one else does and as much as it can physical much of the time it's mental.

Well, I am very accurate as attested to by both Kegel and IRTC. I am also in good control of ballspeed and rev rate. I am averaging 230+ in leagues and most tournaments.

The problem is that I have reached the end of what I can do. I need to improve my power at the pins (getting more off hit strikes) like the kids if I want to compete against them.

So bowling this weekend in a couple tournaments I determined that my thumb just could not get out of the ball before my ankle and that I was muscling my swing. So between games 2 and 3 of 5 I went to the local shop and asked them to drill me a new thumb (switchgrip) moving from 3/16 rev to 3/8 reverse. In game 3 I worked it out (manually ovaling) and threw it near the end. Immediately my thumb cleared, my finger felt th weight of the ball and the ball speed jumped up 3/4 of an MPH. By the end of the day, making the cut and eventually winning the event I was inside 23 throwing to 10 with 16.5 (a good 1Mph more and a significant increase in rev rate). I was throwing some sharpnel, getting a few bird dogs. Succesfully increasing the power at the pins

The more I relaxed my armswing the faster the ball went. So I think I am onto something here.

(Bowled Sunday in another event and did not fair as well, finished 9th... still a good showing)

When athletes reach certain limits in ther ability,  no matter how successful they may be, they can incur more damage by trying to increase or improve their abilities...i.e. they lose their ways.
You need to understand your physical attributes are what they are and no matter what you want to do, you may not be able to change them...you are who you are...not someone else. When you change your natural attributes you can drastically effect the overall outcome as well as incur injury.