Earlier quoted context omitted.
Where did you get that from? WMATA’s farebox recovery ratio is 24%, as of 2020[1]. Edit: And from a quick look, that’s high for the US. The average seems closer to 10-15%. [1]: https://en.wikipedia.org/wiki/Farebox_recovery_ratio
2020 data is totally wrecked because of Covid. Check the 2019 data for comparison. Average is 39%. NY was 54%, WMATA was 39%. https://www.transit.dot.gov/sites/fta.dot.gov/files/2020-11/...
Nationally in millions, Bus: (Fare Revenues 3,778) / (Operating expenses 16,110.4 + Use of capital funds 3,0444.7) = 19.7%. They also break out Bus Rapid Transit which is much worse 16.1 / (166.1 + 51.7) = 7.4% as is Commuter Bus 57.9 / (597.7 + 170.7) = 7.5%
Washington Metropolitan Area Transit Authority, Bus: $124,011,141 / ( $731,946,008 + $182,850,687 ) = 13.6%
So for WMATA forgoing Bus revenue wouldn’t move the needle very much.
PS: And that’s ignoring the overhead of collecting fairs. Not only are some operating expenses devoted to collecting fairs, busses can move faster if people aren’t stopping and fiddling with payment.