If working from home becomes the default then wages will fall because employers will be able to select employees who live anywhere. Working in a physical office constrains the labor supply to workers who live nearby (or are able to relocate).
It will fall for people living in high cost areas like SF and NYC, but it will rise for people living in low and mid cost areas like Dallas or Cleveland because now companies in SF can easily hire the best developers in Dallas cheaper than average developers in SF by paying them more than the average Dallas rates.
This could work both ways. Workers have more options for employment meaning they can jump to a higher paying job without having to uproot their life.