A lot also happened on the road people drive over. At some point, the mission walls were breached and a road to the city ran right through the courtyard. City growth finally enveloped the mission. People assume the famous "shrine" facade is facing outwards, when actually it faced inward to the courtyard.
So, you can drive your Buick over ground where brave men died. I'm for closing off the road, but the rest of the plan is wrong, and they should leave the cenotaph alone.
‘...leave the cenotaph alone.”
As well as the line in the sand (legend or not).
And... just for the record... it was also a church. Probably people buried under that road.