Maybe, but what proportion of stops end in an arrest?
A largish proportion of cop traffic enforcement & safety activity ends in a tow, but we don’t expect traffic enforcement cops to drive tow trucks. The traffic safety people can call out the regular cops if they need them.
> if you run and they can't chase, how do you expect arrests to happen?
Recording devices, reports, follow up. Chases are a public menace, especially when they do them over minor offenses, as is the case for the overwhelming majority of chases. Given the danger, I’d much rather anyone who’s not an active danger to life get away than a car chase occur. The evidence is pretty far on the side of “these are net-harmful”. Cops just like them a lot, so we keep doing them (many places do, anyway—some have all but eliminated them)
Risk of added charges, potentially more serious than the original offense, means the majority of folks facing arrest won’t flee, anyway.