My company operates/ed a job board and a staffing business. Both ran like traditional job boards (Indeed, Zip Recruiter, etc) and staffing companies (Kelly, Adecco, etc.), except being focused entirely on the formerly incarcerated. This is how large employers source many, many employees.
The staffing business was much larger. In this model, we serve as the hirer-of-record, and essentially lease out the workers to our client employers, who cover all our costs (wages, unemployment insurance, taxes, etc.) plus our mark-up (profit). It's a high volume, low margin business.
During the Great Resignation, we found it took 10x the time and effort to get someone placed, eroding our already thin margins. Plus, if a worker left (which they began doing at a great rate), we're obligated to replace them. All of this made it pretty much impossible for us to make money. (Again, we're a for-profit business). I hope this clarifies things.
Of course, there are a lot of things going on. However, I think one important thing is that American workplaces, over the last twenty or more years, gradually accumulated immensely toxic/abusive cultures. At the point of the pandemic, when many people had unemployment/work-at-home/savings, a lot of workers' had their tolerance of that interrupted and then just refused to return.
The thing with the situation is toxic work environments basically are going to double down on their claims, their view of what a sane environment and reasonable pay are. So these organizations are eating through employees and so they'd be the worst customers of a job board. The question how much 70m Record vetted their customers.
Article explaining the toxic angle: https://www.greatplacetowork.com/resources/blog/how-toxic-co...
Employees discuss their views: https://www.reddit.com/r/antiwork/