When thinking about market value, it's important to think about the total addressable market. I see four major types of users:
1. Professionals who need a high degree of mobility - Police and security, Couriers, etc.
2. Tourists who want a special experience and to cover much ground.
3. People who need assistance with mobility.
4. Tech forward adopters who want to always use the latest technology and gadgets, but who aren't necessarily required to have them to function day-to-day.
While these groups are not mutually exclusive, their needs and drives are quite different.
Next I would want to think about the US population that's available for each of these groups. From this list, I'd want to prioritize Professionals and those with Mobility. They are both durable users who will regularly use a solution. Tourists are occasional users. And tech early adopters are a smaller group due to requiring high discretionary income.
While mobility could open up some new product potentials, and have a different funding source (e.g. insurance providers) I'm going to set them aside and focus on professionals.
Within the professional group, I'd further break it down to outdoor / indoor users and professional / private users. Next, I'd try to define the market size potential for each. This would be influenced by the context and ability to buy Segway products or get company or governments to pay for them.
From there, I'd figure out the total addressable market for Segway products, make an assumption about penetration rates and net income per user, and apply a multiple to come up with the total market value.