Can someone enlighten me about the Metro Transit?

Is it supposed to be a public service (re: free)? Bc if not, as someone who just came through the city, I was surprised at how there was no real checkpoint to ensure fares were paid, especially the light rail. I couldn't believe I could just hop on a platform with no barrier to entry, get on that train, and just go to my next destination. Even more surprising was with the bus, I saw people just hop on their merry way without tapping or showing the bus driver anything, myself included. I did end up buying the daily $4 pass, but being new, I didn't know I was supposed to even show the bus driver the pass and the bus driver didn't even say anything the 6 different times I rode the bus lol.

All that to say, if the metro transit truly is just a public service at no cost to the public on the front end, that's cool. But on the other hand though, with the metro transit continuing to expand in the future, how will it stay funded like this, especially if ridership is tracked via fare purchases (bc Idk how else they're measuring ridership) and/or solely funded through fare purchases.