To answer your questions:
Any engine can last over any mileage if taken care of and maintained.
ALL rotaries have redlines and rev-limiters. Since rotary engines generate more heat than piston engines, higher RPM can melt components in the engine, Mazda even uses redline alarms to tell you that you should shift before you begin the damage. Also, it's just stupid to think that it can just keep revving...where would it stop? Where would you shift at? Think about it.
Mazda exclusively owns the rights to use the Wankel Rotary Engine in automobiles. It legally can't be used in other companies. However, in the '60s and '70s, other companies, Ford, Chevy, among others, attempted to make rotary engine cars, but gave up because they couldn't figure how to best use the engine. Back in the '70s, Mazda used the engine in all of thier different model lines as special models, but quit doing that after the fuel crisis since rotaries were only getting sometimes around 9mpg while the piston versions were getting 20mpg. Also, rotary engines scare a lot of people because people don't know how it works. Most people don't know how to properly maintain it either, and then they get pissed when it floods or breaks down which most of the time would completely be thier fault.
Yes, Mazda owns the exclusive rights to use it in cars.
The rotary has been used in many Mazdas, all RX cars, R100, Cosmo Sport, Eunos Cosmo, Luce rotary, Mazda REPU, Mazda Parkway, Roadmaster, and people often plant rotaries in such cars as Miatas, 323s, GLCs, B-series trucks, even 929s.
