I think the loss of payload is a big factor.
A modern 4-seater plane (SR22, TB20 kind of thing) has about 500kg payload. Actually that is pretty good going.
Put in full fuel and you are down to say 250kg.
Put in full TKS and you are down to 150kg.
Put in a chute and you are down to 100kg
You can play with the numbers but it is not insignificant.
Cirrus got away with it because it gave them a huge marketing advantage. The extra fuel burn due to that and the fixed gear is not questioned.