Bottom line is most shooters prefer SFP, and it takes only a quick look-through between FFP & SFP for them to adopt this preference.
Even if there was something better about FFP for LR shooting(and there isn't), shooters would still choose SFP. I think we, and competitors, choose SFP and also MOA instead of MILs for a very similar reason: PRECISION of aim.
Just for example
If this scope were FFP, you could not see the reticle at lower powers, nor the target at higher powers: Ultra-High Magnification 8-80x56mm March Riflescope « Daily Bulletin
Truly, FFP scopes will never match the potential of SFP scopes.