There are loads of aeroplanes around Europe in the microlight/ultralight/ULM and LSA categories that are really very good - even if I don't personally know the three you've mentioned.
Why aren't they more successful than they are? Well, the categories are indeed very successful, but...
- They're generally approved for day/VFR only
- Payload is usually very marginal on the higher performance aeroplanes
- In many countries the higher performance composite aeroplanes get away with lower structural safety margins that won't get through VLA or 23.
- The best ones cost many times the price of, say, a second hand PA28.
But you are looking at a large successful niche, even if those specific aeroplanes aren't so successful.
G