There are various reasons to dislike such a model, especially for an IDE, not the least of which is that the point of a well-designed IDE like LightTable is that it's easy to use and does not require a support contract.
Lots of BigCo are paranoid about the support contract thing. Sometimes partners and investors want to see support contracts in place as a security blanket. In those cases, the support contract for a "well designed" IDE in your scenario is just free money.
JetBrains seems to do alright selling IDEs. In their case, I think people pay for the value, and they continue to pay for upgrades. Support is through the web, so it fits in with revenue commensurate with value.
Yes, indeed. JetBrains uses a closed source model and that works really well (they have a "lite" open source version, but the version they earn money from is closed source). I'm not saying that you shouldn't do support at all, just that it shouldn't be your primary business model.
Lots of BigCo are paranoid about the support contract thing. Sometimes partners and investors want to see support contracts in place as a security blanket. In those cases, the support contract for a "well designed" IDE in your scenario is just free money.
JetBrains seems to do alright selling IDEs. In their case, I think people pay for the value, and they continue to pay for upgrades. Support is through the web, so it fits in with revenue commensurate with value.