My first bluetooth earbuds were the Sony Ericsson HBH-DS970 back in 2006. Back then batteries were bigger so it had a pendant that hung down, and on that it had a little display on it that would show the names of the paired devices and you could select one. It worked great.
A DIP switch, really? Could you imagine the horrendous usability. Plus all that mechanical movement will surely cause early failure. Much better to just have some solder pads. With the cost and performance of USB/battery irons these days surely most users can keep one handy. This completely solves the challenge of accidental pairing and helps the user ensure each device switch is contemplated and intentional.
The AirPods are the best recent example of people who haven’t tried the new thing crapping on it saying the old ways work fine. Multiple times people have crapped on the AirPods and I gift them one and they realize how amazing it is to not have wires at all.
Back in December 2019, the company I worked for gave everyone AirPods Pros for Xmas. Lots of people tried them and complained a lot. I have a pair and rarely use them, only with devices that don't have a headphone jack.
Having no wires was not life changing, I don't really care about that. Running out of battery sucks though. The noise canceling really is great, but they never last a full flight, so I always need backup headphones.
A backup cable is definitely still a useful feature on Bluetooth headsets. My Bose QC-35s seem to only be able to pair with two devices at a time.
I always switch to the cable if I want to use them with my Linux laptop as repairing is a pain in the arse.
I've also found the cable to be very useful for anything that requires both sound quality and a microphone at the same time. Over Bluetooth and even on my Apple stuff they seem to switch to the headset profile to use the mic and the sound then becomes aweful.
I lost my original Airpods about a month before the AirPods Pro came out. It took about a month to get my AirPods Pro. During that 2 month period I used wired headphones and hated every single minute of it. The cord was always in the way. Once, on a crowded bus, the cord got caught and the headphones were pulled out and ended up dragging on the bus floor. I tossed them and bought a cheap pair of Bluetooth headphones for the final 2 weeks. They were crap but at least there was no cord dangling about.
A toggle on the headphones -- a slide switch for Device A or B.
(Auto software switching would be better if it worked 99%+ of the time.)