No Mazda rotary will ever expire if they're taken care of. If you take care of your engine, i.e. maintenance, oil change, filter change, etc. it will most definitley last.
Here are some care tips for rotary engines: http://quazen.com/recreation/autos/the-care-of-a-rotary-engine-rx-7s-and-rx-8s/
Many people have problems with rotary engines because they don't know anything about them or how to take care of them.
The rotary engine is a great engine and can be quite reliable if PROPERLY MAINTAINED. For people who know about their engines and maintain them properly you can get 200K miles out of them. Remember that publications like Consumer Reports generally get their data from average schmucks who change their oil once-a-year whether they need it or not, and consider their vehicles to be an "appliance"...like a toaster or refridgerator.
Unlike a piston engine where regular folk ignore them, a rotary MUST have regular oil changes (every 3000 miles) and you MUST run them hard regularly to clear out carbon build up. Carbon build up is more damaging to a rotary. Piston engines don't like running to redline...it's hard on them. By contrast rotary's relish and need regular runs to redline. You cannot 'granny' a rotary. Too much carbon will destroy apex and rotor side seals. The automatic RX8's are more prone to this as the owners tend to be more conservative drivers who won't push the motor as hard.
Look into adding extra lubrication by 'pre-mixing' 2 cycle engine oil into your gas. This is, in many rotary engine experts opinions, a way to greatly add reliability.
If you buy a boosted rotary, or plan to add FI to one, be conservative with your boost. Rotary's gain tremendous power when turbocharged or supercharged, but it will also shorten its life if the engine isn't well-tuned. And over-boosting will destroy a rotary very quickly as detonation will blow a rotor or apex seal almost immediately.
The Copen uses a JB-DETi engine which is a traditional piston driven engine and is maintained as are other cars. Since Diahatsu is Toyota, we can expect it to last.
