I feel like you're ignoring a key point here, which is that these stingray devices can MitM your phone by forcing it to send essentially unencrypted messages. That's both more technically complicated and more serious than passive tracking.
In 1990, if you walked to the store without telling anyone where you were going, you were basically a ghost as far as anyone else was concerned. In 2020, even if you leave all of your digital electronics at home, you will probably be detected by someone else's electronics.
Earlier Harris equip did that by forcing 2g mode but 2g is being turned off: https://1ot.mobi/resources/blog/a-complete-overview-of-2g-3g...
I'm less familiar with the capabilities of current IMEI catchers tho.
Even if the carriers switch off all their 2G towers (which happened here in .au years back), I wonder how many handsets will still happily connect to a Stingray-type device that offers it a 2G connection?