Bus services from Aiport

My flight landed at around 6.30 PM and it was about 7 PM when I got the bags and since I didn't have any plans for the day, I thought I'll take a bus if available to Palayam and then head home since I frequently use airport busses in Bangalore and Hyderabad. However I was very suprised to see this board in the airport that there are no busses after 6.30 PM. And I could see a lot of arrivals at that time. Even in the international airport where a lot of arrivals happen in the morning, the first bus is only around 9 AM. Not sure why KSRTC is following office timings for the busses and not basing the times on flight arrivals and departures.