Vendor sustainability is questionable at best. I hear this most of the time, that those companies will be there in 20 years when the world turns upside down and

Vendor sustainability is questionable at best. I hear this most of the time, that those companies will be there in 20 years when the world turns upside down and you can always hunt them for fixes, support etc. In practice, however, at least in my country, it doesn't happen. Vendors of course gamed the system.