I think the target market has a big influence here. For end user software, it's not such a big deal to drop support. But for a project like Basecamp, business

I think the target market has a big influence here. For end user software, it's not such a big deal to drop support. But for a project like Basecamp, businesses are buying it and potentially investing a lot of time and money to integrate it into their processes. Companies buying that kind of software expect it to be around a while. It's a bit disingenuous to sell to them knowing it may not be supported after a short time.