It sounds obvious on the surface but higher wages don't always equal happier staff or more output.
I don't think the staff making 500k at OpenAI will be measurably happier with another 100k, for example.
But there is definitely a lot to be gained by getting staff as far away from a sense of poverty as possible and ikea might have helped their line workers a lot with this change.
500k in the Bay Area is very different to 100k, especially if you have a family. So I think that would make a massive difference in happiness.
I think 5 times any salary affords you greater security, flexibility and opportunities that have to make a measurable difference in how happy you can be