But what other options than going dual-license do you have if you want to do open-source in a sustainable way? MIT does offer nothing here, unfortunately.
There are many good business opportunities if your open source technology, without strings attached, gets popular. You could just sell professional support as part of subscriptions and verified builds. Later on, when you release a new version, you can still support the previous one or build migration tools that you include with subscriptions, etc.
That's true, but on the other hand there are also successful (A)GPL open source projects … think of Linux (or MongoDB, at least for a long time).