"I have a different take on it.
Why do the motorcycle vendors being their models to show off, let people touch them, even ride them? Is it so they can make a sale on the spot? No. It's to convince the potential buyer he is looking at the best product available and come to a purchasing decision.
If you bring nothing for your target audience to see then you've made a zero impression for any potential customers. And the competition scored a hit over you by going after the same target audience.
Motorcycle manufactures such as Honda, HD, Yamaha, whoever don't expect to sell their bikes at trade shows. For them its cheap advertising in front of a target audience. Everyone else expects to make money, people selling trailers, clothing, accessories , and anything else. I know of no one who doesn't bring a sizable inventory to any show. The problem is your taking home almost all of what you brought. That's not a opinion its a fact. So when you spend $6-10k in expenses for a 10 x 20, you do all the work of setting up, selling, hiring help, breaking down, traveling to and from and you don't brake even let alone make money and you don't see any results on your website, what's the point of doing it? Even at Americade attendance is way off what it was ten years ago. Motel vacancies abound and the same can be said for all of the big rallies. All rallies are way off, not just down, way off! Even the once popular BMWMOA national along with the GWRRA's Wing Ding haven't done well the last couple of years. Small events like the popular Finger Lakes BMW rally at Watkins Glen Labor day weekend are barely hanging own. At one time that event had twenty great vendors for the 1200-1400 people that showed up. Now their lucky they get half the attendance and maybe one or two vendors at most. I've done many small and large events since 2005 and the last two years it simply wasn't worth it. The IMS shows have really cut back their schedule to half of what they use to be and I wouldn't be surprised in another year or two they simply go away. So for us we'll only do a few events for fun in areas we wish to visit and put our effort into a Amazon store which in only its first month seems way more promising then any trade show we have done in the past few years.