While I wish I could have agreed with you that bus lobby has no influence at all, it is for everyone to see that the maximum crowd from Bangalore towards Kerala is on Fridays (evenings). But look at the trains that run on Fridays (only 3) whereas other days it is as follows (Mondays-5, Tuesday-6, Wednesday-4 & Thursday-6. Seems to have all slots on other days but seem to have issues on Fridays (after much pressure etc, last year Humsafar was started but due to terminal constraints was moved to BAND)
A comparison of rates on buses on weekdays & Fridays can also give you some idea.