The increase post lockdown could be due to 3 reasons - 1. Freelancers losing out on business due to Cost control, 2. People laid off now looking to earn, 3. More companies looking for freelancers to tide over this period.
There are two important points though, 1. The search for freelancers took off by the end of 2019 probably due to the slowing economy and yet 2. It is a mystery why freelancer search was so high in early 2016 when the economy was doing quite well