Those are still nothing high at all. Thirty second test is not indicative of typing ability, just sprint. As you can see, vonunov (i.e. Jack) has gotten 200 wpm (I'd assume on a short test), and scores in the 150s often. Again, 140 is not an impressive score for typists who have been using layouts for years and years. Colemak has been out for quite some time, and the standards are by NO means arbitrary. 120 can be reached by typists with poor technique, but anything above that requires technique.
Again, no good typists. Even in the 1970s, typing schools showed off their best at able to type over 150, on a typewriter. 140 is a rookie's score.
The point is that you claim to have made repeated searches, but it seems you haven't. Within a minute of searching I found scores that would suggest otherwise. It seems sort of dishonest to claim that there are no fast Colemak typists when you have not searched everywhere on the internet and especially not everywhere in the world.
Whether the speed of the typists I mentioned is considered "fast" is subjective and not relevant to my point.
If you're going to make a claim, I think that you should at least give the sources of your information and the basis for your standards of measurement. Yes throwing around 150wpm is an arbitrary standard unless you give the reasoning behind it. What is the base you are looking at? It's certainly not hi-games. Typing for how long? Punctuation included and actual sentences? Are we talking about fastest wpm or average? You haven't given any standards.
Okay 30 seconds is a sprint. Note that there are no Dvorak scores over 150 on hi-games except for the 30 second test. For the 1 minute test, the highest non-QWERTY score is from a Colemak user (148wpm). For the 2 minute test, the highest non-QWERTY score is from a Colemak user (140wpm). For the 5 minute test, the highest score is 134wpm from Jack.. is this the Jack that you are referring to? His highest score on any test is 145wpm.. clearly a rookie by your standards. There are tons of QWERTY scores over 150wpm. Where are the fast Dvorak typists? If the fastest typist is somehow a measure of the worth of a layout, then it would seem that QWERTY is this best. Of course other things matter, and I think you put too much emphasis on the layout itself when it comes to speed.
Well obviously I was only looking at one website for the last paragraphs (I specified which one it was though). What other sites have you looked at that list the highest typing speeds of users and their layouts? Looking at typeracer's vonunov, his record may be 200wpm, but his average is 129. His most recent scores are 162, 145, 133, 130, 123, 129, 131, 154, 124, and 105. That's quite a range with only 2 scores above 150.. so is he just another rookie? A good typist for sure, but he's also just a single person.
Another factor is the legitimacy of scores. Let's look at the rest of the best of what typeracer has to offer. mrcam1987, ranked 4, types at an average of 197wpm on Dvorak with a best race of 305wpm. This guy's average and highest race actually destroy Sean Wrona (who has an average of 189 and a high of 254). Seems a bit ridiculous to me. Is it a legitimate score? I don't know. Maybe, but we don't really have a way of knowing for sure (unless you know more about this person than me; he lives in Cambodia apparently and I couldn't find out anything about him). He does have an alternate account though with a full average of 61wpm.
Continuing down the list, it took about a minute to find a Colemak typist who types over 150wpm. So much for your repeated searches? shrimpneck has an average of 151wpm and a best of 203wpm on Colemak. His latest races: 101, 202, 188, 195, 178, 195, 200, 199, 202, and 197. This user has much better stats on typeracer than Jack. Are they legitimate? I don't know. I honestly have no idea how difficult it would be to fake high scores on a site like typeracer or hi-games.
That's the top 20. 1 Colemak and 1 Dvorak typist. In the top 50 I found a Dvorak typist with roughly the same stats as shrimpneck called rebel2000. I stopped at 50. The way typeracer organizes the top racers is admittedly annoying, but everyone else in the top 50 either specified QWERTY as their keyboard or did not specify a keyboard. Where are all the fast non-QWERTY typists? I think at 150wpm, things depend more on the typist and not the layout. There seem to be very few 150wpm+ average typists for these two websites for any alternative layout, so I do not see why you give that as a standard.
I think it's also important to note that Sean Wrona's high score is 254 on typeracer and 205 on the thirty second sprint on hi-games. This is just one example, but obviously there are huge differences between typing at 150wpm+ on hi-games vs on 10FF.
Like you've said before, the number of people using the layout and the age of the layout matter. Dvorak was created in the 1930s. Colemak was released in 2006. I think that it hardly can be said that 7,8 years is long enough to have as many fast typists as layouts that are so much older. I don't think it really matters anyway. To call Colemak useless for speed an accuracy based on no data and only the assertion that there are no fast Colemak typists based on only your limited observations seems ridiculous. If someone was actually going to conduct a study on how "good" a layout is for speed and accuracy, they would first set standards for what is meant by that and then devise some test to measure the relative performance of a similar group of people over a long period of time switching to the different layouts controlling for differences. They certainly wouldn't just look at the anomalies.
I'm just saying I don't think you have enough information to draw these conclusions