Greeb: casual games are not necessarily aimed at the short term. That's just the mainstream perception.
Angry Birds is as casual as they come, and it is every IP's wish. Candy Crush, Peggle, Plants vs Zombies, Snake, etc. All casual and very succesful games through the span of several years. You don't need to be at the top of gross profits to be a VERY successful business (Minecraft is an example).
Truth is there are many, many things that make up a good game. You don't need to be a competitive game to last through the years, but like Inverse stated, it seems to be the RTS's tendency.
The strategy genre (in general) doesn't need to be competitive to be successful (Civ V), but in all honesty, in the case of CoH, it is what kept Gamereplays alive and it was members of the competitive community that started CoH2.org. It is only logical that those players would want CoH2 to be competitive.
Is it bad if CoH2 remains tailored to casuals? No, it isn't, if people keep enjoying it. However, you can't expect the competitive community to stick around, either.
I think otherwise.
Almost all casual games have a short life span. The very Zynga, developers of farmville and a lot of those type of games, is in a dire situation. Also, those games have their target in phones and tablets. Console and PC games follow another rules, due mainly because people don't play them while taking a dump or waiting the next bus.
Games as Candycrush are like teenager pop-stars. They make a lot of money and disappear the next year.
Competitive games, instead, are like old rock stars. They still do music in his death bed.
Casual games survive releasing a new iteration of the game each year, like CoD, Battlefield, FIFA, etc. Because the game itself is boring and lack a catchy gameplay, so developers have to introduce novelties quickly. CoH2 is falling in that mechanic, were the playerbase only appears whenever a new patch comes, and disappear again a week after.
Competitive games like CS or Starcraft release a new game only when the game is becoming technologically obsolete. Seriously, I think Valve is really great doing that, making money selling hats and stuff while the competitive aspect of the game is untouched.
The only right step I've seen in Relic approach is Steamworkshop.
Any good game without a huge playerbase really need mods and customizing tools. CoH1 success was that the game was great, but also that it had plenty of mods and game modes to appeal a great variety of public.
BTW, I don't think minecraft is a casual game. On the contrary, I think is the opposite, or at least started as the opposite.