The article shows no such thing. The crowds of people are not the root cause most of the time - if the buses would come at regular intervals, statistically they would all have the same delay because of passengers. But if a bus is already delayed ("if Bus B is delayed by traffic congestion, it incurs a penalty"), there will be more people waiting, which will slow boarding, which leads to more delays, which leads to even more people waiting at the next station etc. But of course, the cause for the initial delay is not always traffic congestion, it can also be a bus breaking down, a large group (e.g. a school class) boarding the bus etc. So dedicated bus lanes (and other measures such as buses/trams being able to influence traffic lights) can't completely eliminate bunching.
Maybe you haven't seen a big crowd. During the day there can be such crowds going to work after 7am that bus must wait for ages then complete cutoff at 9am then some bumps around lunch then another craze at 4-6pm and this even without irregular local events like as you say groups of students
Bus lanes are good but it's driven by crowd sizes and a lot of combatting bunching can be done without adding bus lanes
Where I live the interval at around 7 am is 10 minute, which drops to 15 after 9 am or something and is 20 at the most chill times. Haven't ever seen an empty bus or really overcrowded one either.
Where I lived recently the interval at peak is like 4 min most. One stop boarding can take 3 min when stop is full. My bus skipped my stop until 9am because bus after bus are full. Skipping stops is one way to reduce bunching I guess
EDIT Who said there's only buses? There are cars, taxies and subway
It's always possible to add more buses or people can just go queue at the previous bigger stop it's 2 min walk away and it always stops there.
The point is that crowds cause bunching. I don't know what is your point
