Keep in mind that dial-up users DO have enough bandwidth for online play. We had massive online servers in RB3D when MOST users had dial-up. I sat down and figured out exactly what the requirements were once - something around 12 KBPS on the client and 12 KBPS per person on the server. I've done similar tests with FB and the numbers are consistent. That doesn't mean every game will have similar requirements, but certainly it is possible to write a flight sim that plays well over dial-up.
I'd also keep in mind that any new sim built with ideas from this thread would be 2 years away at a bare minimum, so the online environment won't be today's environment but rather the one 2 years down the road. That means a greater percentage of broadband/always on users and a greater percentage of dedicated phone lines for the remaining dial-up users.
And I don't think the assumption is that everyone will want to be connected to play. I think the assumption is that if connecting is a requirement then it will be one that the vast majority can live with. There may be a number of users who would prefer not to connect, but I don't think there would be many who would be unwilling to connect. Heck - there might be users who would prefer to play with their computers turned off. You can't make everyone happy...
Developers need to innovate, and much of the innovation is going to be based on interoperability over the Internet. As more and more users get connections that are always on, there should be a trend toward using these connections to enhance the gaming experience. I don't think that someone should say 'you can't do that because that's not how it is done.' I think there needs to be a better reason not to do something than just that it hasn't been tried before.
