While I don't want to start another discussion about pro/cons of Unity, I'll just throw an interesting fact in here:
This whole discussion has been going on for years. Quest 3D, Genesis3D, Vulpine, Jamagic, Irrlicht, Ogre, <insert any other competitor tool here>
Still, Acknex has existed well over 10 years now and it doesn't look like it's dying soon. Sure, some users will switch engine, that has happened before and some people disappeared almost completely. But other users have joined instead and the user base has grown remarkably over the years.
Apart from that: Conitec has to make the best of their current situation. Maybe the gap is too high, but this can't be changed now. Recruiting more and more people is a question of money as well. I know they buy useful stuff done by users or grant them a pro edition to save some work time for other things.
