Well I expect CoH 2 to last another ~6 years as its predecessor did unlike BF and CoH who bring out a new game nearly every year.
It's already been hinted at by a Relic dev somewhere in these forums that we can expect a CoH3 in a much shorter timeframe than that of CoH1 -> CoH2. The CoD/BF/Fifa/etc model may not suit the videogame snobs who bang on about quality over quantity (I'd be lying if I thought I didn't fit at least a little bit into this category) but it's a damn effective business model when you can just recycle and reuse a bunch of previously made assets, allowing you to pump any excess money into advertising and therefore secure regular high profits.
And personally, I think it's already patently clear that CoH2 will not last 6 years. For all those that say it's just early days yet; it's a fair point. However, although balance can be tweaked, design post-release is pretty much fixed, and that design is coming from the team behind OF and ToV. Just putting it out there, Q. Duffy was the lead designer for the Brit faction; no comment (and nothing meant against the man himself), because that's great if you loved the Brits, but isn't so hot if you weren't a fan.