Increasing fares has led to decline. Fare-free make economic sense.

Fare free transit makes both moral and economic sense, and would be a critical step in fighting climate change. The MBTA has increased fares 4 times since 2012, while ridership has continued to decline. Cities that have adopted free public transit, meanwhile, have seen ridership increase as well as a surge in transit equity. Furthermore, fares from bus and subway rides amounted to just over 20 percent in revenues for the MBTA budget in 2018, a gap that could be filled with new progressive revenue if fares were eliminated.

https://medium.com/@jordanforma/public-transit-is-a-public-good-1095ae7df8e9