By that same token, how big are the companies at the end of the tail? If large corporations are cutting marketing budgets, small shops on tighter budgets probably are as well
Not every other guy would have a tighter budget. Companies like a gaming company, a streaming platform, home delivery, edtech, telemedicine, D2C brands to name a few are the ones which have increased their budget during these times. Adding that to the fact they get better ROI on Facebook ads mean they will end up spending more (and getting more value in return).
Big brands cutting spend on positive ROI is probably foolish, especially if it lets your competitors increase their ROI. For brands like pepsi that don't sell online, then it's just a cost center.