With so many companies having layoffs in the last 12 months, were those all unnecessary jobs? If not, were revenue targets or company valuations lowered to match the loss of productivity with fewer necessary positions in the company?

Companies will absolutely continue paying large numbers of employees to do unnecessary jobs, they're incentivized to do so. A growing company is often seen as a good sign by shareholders and no one can really tell whether the new roles are any more or less productive. Existing employees and managers have the benefit of growing teams and getting promoted before anyone sees if the teams over-hired. Holding expendable positions also has the benefit of making for an easy layoff when investors get spooked.

Meaning the company and employees have good reason to hire and keep unnecessary jobs, don't have many short-term downsides as long as it doesn't directly cause a drop in key metrics, and have a built-in backup plan when things turn south and they can show good leadership by trimming the fat.