I think the problem is that, from the dealer's perspective, the reason for a test drive of a cage does not apply as readily to a bike.
Yes and No. Take to long to explain my thoughts
As the customer, WE view the test drive as a way to gauge the comfort and handing of the vehicle. But honestly, we would need a weekend to really do that.
Comfort and handling - to what extent I ask? Once I hop on a bike, I want to test a number of areas, especially if it is 2nd hand. Things which are either bad about it(as in faults easily discernable), or if I am simple simply not comfortable "with" the bike / car. Comfortable as in not being in a cramped riding style etc. These types of things can be picked up quite quickly and ARE important.
To feel comfortable as in 'now I know my rump doesn't get sore after X hours', well, you won't find out about in a 30 min test ride / drive. But for problem solving or ensuring a comfortable riding / driving position, yep, a brief spin will let you work that out.
The dealers view the test drive as setting the hook. It is very rare that a test drive does not result in an immediate sale. The salesman is in the car, and the whole time is distracting the driver pointing out luxury items, and basically, cementing the sale.
Then it's back to the dealer for 2-3 hours of one-sided negotiation.
Don't you just love the old - "I'll just have to see if I can get that for you, let me go and talk with the finance manager" and stuff. I prefer cash. Bought two vehicles, the ZX12R and a little BWM car in the past 10 weeks, with cash.
Bikes tend to sell themselves, and a test ride would make little difference in whether the purchase is made by the majority of customers.
Where I come from, well, the test ride is very important and if you know EXACTLY what you want, then the test ride may not be so important. Outside of that, I'd have to say that out here in Aussieland, without the test ride, a decent one at that, there's no way the dealer will keep the customer from going down the road to someone else. Mind you, they do their best to ensure you aren't a tyre kicker looking for a blast on a bike for free, before you get out on the bike, but still..
Anyways, could just be the vast differences in the market, the checks before things and also, cultural, which make test rides and drives (some for the whole weekend too), such a different thing between USA and Aussie.