I think that the real answer might be something quite embarrassing, and politically incorrect.
- We really don't know how to deal with the differences, and it is scary to try;
- There are some company process that we are afraid of changing to accommodate telecommuting;
- The risks and costs outweigh the benefits, or the benefits are fuzzy while the risks and costs are clear;
I'm curious what you think it might be. I would guess here but lack experience to guide my guess.
I gave it an up-vote anyway, because this is an interesting and highly relevant topic in the tech field, though I'm dubious of getting any substantive responses from anyone who's any kind of manager.