How about I try these questions regarding a pipelauncher for the fun of it.:
"1. What is your target market for your private sector enterprise? Space tourism (orbital or suborbital)? Launch services? Satellites? Deep space probes?"
Launch services.

"2. Approximately how much would it cost to enter the market? Be sure to include the cost of government regulations in your price. For things like space tourism, at least in the US and probably much of the rest of the world, regulatory compliance costs can be enormous. It costs millions of dollars to certify a new private plane design for production and millions more to certify the production facilities. The more complex the vehicle, the more it costs to certify."

It depends. To build a pipelauncher, which is mostly a launch pad which only adds small amount of added speed, it could be less than 1 million. Probably would want to start with somewhere around 100 mph and operate it conservatively- about 5 million to make.

"3. How big is the market for these services? Be honest now, how many people would shell out $100,000 or more for a brief space trip?"

Existing rockets generally have a launch site, but currently I would guess the rocket makers worldwide are spending over 50 million per year to use a static launchpads and are probably spending as much money getting their rockets to their launch pads, has it would cost to ship them to a ocean launch site.

"4. What are the spin-off marketing opportunites and how much can you realistically expect to raise?"
You can paint logos on side of pipelauncher. There should some public interest in just seeing the pipelauncher launch, and any launches in general have public interest. Might be enough to cover fuel costs per launch (not much money, about $2-4,000 depending on payload weight and accelerate rate)

"5. What are your legal liabilities?"
Pipelauncher would need to prove it was safe, but it should quite safe if operated within certain margins.

"6. Factoring in everything, what is the projected return on investment? Be honest now - the economics of wishful thinking and unrealistic expectations have killed countless dreams."

A pipelauncher could cost considerable less than building any launch site on land. A pipelauncher would cost less than used oil platform. And comparison to rockets, a pipelauncher is dirt cheap. A pipelauncher is reusable, but even if it only had one use like a rocket, it's would probably be worth the cost of construction. The fuel used to accelerate a rocket to 100 mph, should cost more money (just the cost of rocket fuel) than fuel used to lift pipelauncher and rocket to 100 mph.
The main value of pipelauncher is it's a launchpad. Next value is it adds some payload capacity to a rocket. Next it would look cool. Next it would save money in terms less fuel used- pipelauncher is more efficent than rockets. Next maybe seen as liability, pipelaunchers have capacity of being improved- if you build a pipelauncher, then someone else will build a better pipelauncher- more fuel efficent, one that handles big rockets, and/or adds more speed.