From some time in the 1900s until the late 1970s, in the US, iirc.

https://www.cbpp.org/research/poverty-and-inequality/a-guide...

Significant wealth inequality gaps and the lack of wage growth, in relation to inflation, coincide. There's a lot of data on this subject, but getting specifics on how the data is collected is very difficult (given the data collection is often decades old).

Yes, as a general rule of thumb salaries track or exceed inflation in the long run. If that weren't the case, everybody would be living in Huts eating gruel