I have never understood the beef with matatus. Matatus are an organic solution which are not going anywhere. Michuki 14 year obsoleteness rule have left matatus standing. Traffic is only a problem for 2-3 hours in the morning and another 2-3 hours in the evening. By 9 most 14 seater to most estates are struggling to fill up.
The numbers say this is not huge- 132,000 passengers per day. The fares are also ridiculous for those who use matatus; makes sense for my car people, most of whom see the car as a status symbol.
Nairobi was planned for a few thousands of mzungu not millions of Kenyans. These are apartheid planning by settlers meant for control - you have to be at the station by 7:30; 8:45 2:30; otherwise you have no means out of town to Kikuyu and such.
Insolvent KR cannot be running these contraptions 24-7! My interactions here indicate you have experience running transport business - the day to day grind is crazy for one vehicle. Now take that to moving only half a million by kanjo by rail and millions by BRT.