For as long as there have been bicycles, there have been bike thieves. That's my guess, anyway.
I also reckon that bicycle thefts increase along with the popularity of cycling. As I've mentioned in other posts, I became a dedicated cyclist as a teenager, late in the North American Bike Boom of the 1970s. Until that time, there didn't seem to be much bike theft and the loss of a bicycle was seen like losing a toy, mainly because almost all bikes at that time were ridden by kids.
During the "boom", for the first time in about half a century, significant numbers of American adults were riding bicycles. While most pedaled for recreation or fitness, a few rode to work. That, I believe, the reason why bike theft was taken more seriously.
That is, by everyone except the police. If you were to report your stolen bike, you'd be told, explicitly or implicitly, that you wouldn't see it again. They had bigger fish to fry; never mind that the person might have been using the bike to put food on his or her table.
History repeats itself, plus ca change, or whatever how you want to say it. Bike sales have surged. So have bike thefts. Worse, methods that haven't been seen since the "bad old days" of high crime have made a comeback. There are reports of bikes lifted, along with the railings to which they were locked, from the insides of buildings. And, in the Bronx, eight men attacked a 15-year-old boy and took the bike he was riding.
Stealing the bike may not have been the ultimate goal in that attack, though the bike was a worthwhile "haul" for the perps. Some of the other thefts may have been "fenced" for quick cash. But, according to reports, some of bikes may have been stolen because of the current shortage, caused by a spike in demand combined with a disruption of supply chains.