Kontakt has no competitors really. There are no standard and open competitors, the closest is maybe something like HISE but it's not even close from a marketshare perspective.
The rest you listed, Soundpaint, Engine, etc. are company specific proprietary samplers. Their only market share is the market share of their own company
A lot of these aren't even samplers?
SINEfactory is just OT's free collection of instruments. Labs is not even a free collection either anymore, Spitfire has done some strange subscription or monetization wrapper around it (and fyi labs used to be on Kontakt).