Ratings were dismal this year for the TDF, some days didn't even crack the top 150 of cable programs for the day or a 0.02 rating (that means only 2 out of 10,000 people) That means advertising revenue is almost zero and cycling already has a limited advertising revenue appeal.
I blame some of this on the inconstancy of the coverage. Some days they bumped it for stuff like "Professional Fight League". Some days it was on NBC in the morning but didn't make the effort to really promote it there.
I blame some of this on the Froome BS, just another black eye that people think cycling is doped, regardless if Froome was innocent or not.
Having top sprinters eliminated or being a non-factor hurt them also.
Drone coverage might be good but how much would it cost the TDF organizers to have them? Live cameras on the bikes might help but when you factor in everything, will any rider add the weight needed for a live camera?