Multiple industries laid off large parts of their workforce. US unemployment trippled, and more tourist heavy countries fared even worse. One of the biggest drivers of crime is "it was the best option available at the time", and most cybercrime isn't highly skilled and fairly accessible.

To make matters worse, "regular" crime struggled at the same time. It's harder to break into people's homes if they are at home all day, and you can't mug them in a dark alley either, neither can you pickpocket tourists.

My guess is with lockdowns you had a lot of people bored at home stuck with nothing but digital screens for entertainment. People with remote jobs or no jobs could be scanning sites for exploits in the background whilst doing other things since they have literally nothing better to do to keep them occupied, not like they can go outside very often.

This is a guess though, but now think of the millions upon millions of people bored at home who might think "I wonder if..."

In some forums I lurk in there was some hubub about massive holes in security that were opened up via people who are used to working in an environment with IT support (somewhat secure, depending), etc, to people trying to figure everything out at home on their own and using new tools (both software and hardware) to do it. Don't know how accurate it is but it makes some logical sense to me.

Because more users online for more hours, more stuff happened online due to lockdown etc etc etc.