I know, most lbs can not stock high end bikes anyway.
I, too, am hoping for the end of the year
The thing is, if you're buying a high end bike, you likely already know your fit anyway, or else can work with a bike fitter to get your coordinates and figure out which size and model works for you. So no real need to test drive it for fit. My experience with Canyon has also been really good on this front - I have one on order (3 month lead time in UK by the way, which doesn't bode well for their ability to scale up and get into the US this year), I had a RETUL fit done a few years ago so just sent them the numbers from that and have had good discussions about sizing so I'm very comfortable that the bike will fit when it arrives.
So if you're not test driving for fit, you're test driving for other factors like stiffness, ride quality, etc. I've been riding road and tri bikes for nearly 25 years, and I can honestly say that I don't think it's possible to make a meaningful judgement of these things on a test ride. If I had the opportunity to get a Canyon, set it up exactly like my current bike (fit, bar tape, saddle, pedals, tires, wheels, etc), and then ride both bikes back to back on the same road, then it's just possible I could make a meaningful comparison. But even then I suspect there would be things I maybe didn't like on the first ride which grew on me with time. If you're test riding a bike that is set up even a little bit differently to your current bike, then IMHO the test is largely meaningless.
When I was shopping for a nice road bike I was advised to make sure I got a test ride on any candidates to make sure they suited me. I did ride a couple of bikes and quickly came to the conclusion that this often shared advice is total nonsense. What matters is fit and even this can't be well checked with a test ride. The rest is all too subjective and has too many variables. How you feel the day of the test ride, the weather, the local terrain and road surface, how well the bike is set up for you (saddle position, bar position, brake and gear tuning) are all far more important than the construction of the bike itself. Tyres and tyre pressure are vitally important to handling and comfort but people reject bikes for comfort when they don't even know what tyre pressure they were riding on or haven't ridden those road surfaces on their existing bike for comparison. Test rides are almost entirely a nonsense.