Remember, too, that this also happens during Holy Days of Obligation.
The issue of the Jewish custom has nothing to do with the idea of the anticipated Sunday Vigil Mass celebrated late afternoon/evening Saturday. The idea was to allow those who could not attend Mass on Sunday to be able to satisfy their obligation on Saturday (after 4PM).
When my dad was in retail, we went to Mass as a family on Saturday evenings. Since he was the sole driver (and sole support of the family–and the Metro has a weird Sunday schedule), the Saturday evening Vigil Mass was perfect for us. Now, I attend Mass on Sundays (and, like you, I will go to the Vigil on Saturday, too, because you never know what creeps up). Just as an example. Three weeks ago, I went to Mass Saturday evening. My eyes were hurting and were red. The next morning, I learned that I had pink eye. I was glad I went to Mass the night before.
Now, my young friend, the only time that sunset is a critical factor is when it comes to the Easter Vigil. It is absolutely forbidden, unless there is a grave reason, to celebrate the Easter Vigil at the same time the parish celebrates the anticipated Sunday Vigil Mass. This means that the Easter Vigil can’t be celebrated at 4PM on Saturday. It must be celebrated after sundown. This is an ancient Church tradition because the Easter Vigil is the Mother of all Vigil Masses and, the Paschal Triduum marks the Church’s highest holy days. All of our holy days reckon from Easter.
I hope this helps you. You’ve been asking some pretty good questions and you’re a pretty smart young man.