I think that oversimplifies MBTA. The T isn’t just the Subway lines it’s a layer cake of networks spread over three states Massachusetts, New Hampshire and Rhodes island. Bus, light and heavy rail, ferry services.
You have what? at-least 8 major modernization and development projects for the rail aspect. South Station, Back bay station, the orange line , the green line extension, Rolling Stock on the commuter line, which is overdue. Draw bridge one off north station hasn’t even started yet. That’s before any pop up issues like Harvard Square. Or the new governor’s want to electrify the commuter rail system which would feed back into rolling stock and demand major changes to all the railways in the greater Boston area.
Oh then the North South connection project that has been boiler plate for at-least as long as the LIRR grand central.
This hasn’t even left the Boston metro area and we’re still on the rails.