Stability, sustainability, EU legislation compliance and taking care of your individual problems. If it goes well, the companies will grow with you and don't outgrow you.

I think there is a growing Digital Mittelstand in Germany already. I myself work for such a company. We have some strong VC-backed competition. So far the company, self-financed, fares quite well.

I think the author misses a plethora of B2B markets when coming up with examples. There Mittelstand can be a very stable, (if desired) regional long time partner.