The Saturday Sabbath Vigil was instituted to accomodate fishermen who worked on Sunday morning, which is why it wasn't everywhere. They are on the boats before dawn and there was no Mass for them, so...it became a Mass of convenience for everybody else.A perfect accommodation. It also relieves the very many people who work on Sunday mornings of the "do I go to work or to Mass" dilemma.
God is a God of common sense, though one would be hard pressed to find Him among some on this forum.
I work on Sunday morning, but I rarely go to Mass on Saturday. To do it regularly without real need is a cop-out. I go to 5 pm on Sunday.