Ok, here's my take. I have 22 aces to date. 20 of them were last year. (All data for my aces including disc, distance, notes, and course links are in my sig so you can verify details.)
8 were on one day (11 rounds). Most people would call it a pitch and putt course, but the kicker to that story is that it was a disc I had never seen before, or read the flight charts on, much less thrown. In that group of 8 were aces ranging from 83' to 128'. One was a RHFH anny, one was tomahawk, four RHFH hyzer, 2 (including my 3rd shot of the day) were RHBH lasers. Did I count them all? Yes. I scored every single round (even the ones that I didn't ace on.)
My first ace was a true "luck" ace. I shanked my drive on a hidden basket 273' shot. Wind picked it up and slammed it in the basket. It was my first and longest.
Average distance of 146.2'. 11 aces have been with discs bought in the previous seven days with 9 being same day purchases. 10 are with putters, 11 are with mids, and 1 with a driver. 8 courses are represented in 5 states.
That's enough information about my aces, so here's my conclusion based on aces I've witnessed, seen on youtube, and the ones I've thrown. Aces in the sub-250' range are often, but not always, intentional. At those distances, there is just enough touch on the disc to run it without ending up 50+ feet past the basket. If I throw a CE Teebird at a basket 350' away, and that disc is still 4' off the ground when it gets to the basket, with that line, I'm going to end up trying to get back for a 3 and if woods are involved, potentially a bogey or more. Aces beyond 250 are often, but not always, I'll say "fortunate." Undoubtedly, they threw a good shot to hit that, but more often than not, it was unintentional. They were likely looking for a birdie and overshot, but the basket managed to get in the way.
Do you feel jipped by your ace count being zero? You have two options. Realize that you are likely playing higher level courses that some of the rest of us, myself included, would LOVE to be playing. I would much rather play a Winthrop Gold, Waterworks, Steilacoom, Delaveaga, etc. than a pitch and putt, but if the P&P is what is close, that's where I'm going to throw. If you would rather hit the shorter aces, then find a course that you can do that.
Sorry this is long, but like these guys have said, keep at it. The first one is always the hardest, but once that happens, keep throwing. They like to come in pairs (or more!).