As always --- it depends.
Developer tools are supported well enough by open source.
Business software is less so.
How important is support and continuity and longevity? Source code is the only support Open Source really offers. If you get something more --- good for you but typically there is no obligation or commitment made in this regard. Even if you get one, it's longevity is suspect. It's really easy to walk away from a software product when it's not paying it's own way.
Most people looking to invest and build a business expect somewhat more than Open Source offers for "business critical" software. And many of these people are not in the software business and don't want to be.