People who aren't used to critiquing art wouldn't pick up on most of the subtle design differences between these two examples despite being visually similar. Spending years in a critique based system will teach you very quickly how to spot the differences.

But like you mentioned further along, if you took 100 designers, kept them from each other and gave them the prompt 'Design a jersey that's based off of the MBTA', probably 90/100 would look exactly like these two examples but would have enough unique design elements that none were copies.

It's probably not a ripoff at all, both are just very heavily borrowing design elements of generic transit maps that could be found in almost any major city.