It seems so perverse to artificially delay a load of passengers because others are running late. But at a system level it probably makes sense.
Like "from 7AM to 11AM, one bus every 8 minutes". Then you have the bus app if you want to optimize further (and if you're me, miss it because of being too tight)
I get why, it just feels like your time is being wasted.
Of course, the trade-off is that next time you'll have a shorter wait to catch a bus or train because some other passengers had to sit and twiddle their thumbs for a bit
When each individual strives for the best result for themselves (a local optimum) we often end up in a worse result for everyone (see tragedy of the commons, prisoners' dilemma etc).