Pretty much this. For a lot of us our playtime is limited as we are adults (kids, family job) so if I'm doing a 4* I'm going to look for a group or folks that know what they are doing. A LOT of us don't have 4 hours for a TF like we used to. Not saying every TF has to be a speed TF, but hard mode is a different breed.
Also anyone who DOES have time to run a 4 hour 4* has the option to form their own team.