They don’t want it because Arlington has a lot of rich enclaves that don’t want the poors being able to get off in the area or spend literally any tax money. Several other suburban cities around Dallas that aren’t as fucked as Arlington have some light rail and bus transit, even though it’s terribly inadequate.

Additionally Arlington is stuck in the middle between Dallas and Fort Worth, which have populations of 1.4 million and 900 thousand, so the train transport between them just skips Arlington since the city won’t spend any money to build stations.