I don't think it's related to gambling or commercial, India has a history to avoid follow- on numerous times be it home or away test matches. The only logical argument in this test match, Virat can give is net practice for Indian batsmen and resting Seamers.
Out of 8, Virat didn't ask for follow on 5 times, well, I think he always wants to bat and have some scored besides his name
so that he can get enough chance to chase S. Tendulkar.
I was expecting a follow on yesterday when WI was 79/7.
I don't think if he cares about records much and surpassing Sachin's record is just a matter of time for him. I didn't see the press conference. So not aware what Virat said about not going with follow on, but I am sure the reason would be more or less same " enough rest for bowlers" we shouldn't disregard that India is playing with only 4 bowlers and in the test match every team wants to eliminate every possible scenario of losing a game first.
2 full days left in the game, the odds are against Windies but imagine for a sec, If they win the Test match. This win can transform windies cricket for good. Chances are dim, but Again Cricket can hit you on guts sometimes.
I think now days most captains are scared to enforce the follow-on after what happened to Australia when they enforced the follow-on against India and then India dominated the Australian bowlers and ended up winning the match. Since then there hasn't been many follow-on enforced by teams as they never know if the team following on bats well. We have seen in the past that teams chasing anything near 500 runs is almost impossible to win the match which is also why most captains decide to bat again.
Fairy tale!! and it changed the Indian cricket tbh. Winning Test against the Mighty Australian team and ending their winning streak of 16 games.