@gargron @citrustwee That depends. "Robota" → "rabota" is a shift in (Great) Russian that occured under influence from South Slavic dialects, Old Church Slavonic to be exact.
In Old East Slavic (Old Russian) this was not the case, so "robotnik" qualifies as a proper archaism, too.
Coincidentally, in most dialects of contemporary (Great) Russian and Belarusian unstressed o's turn into schwas which produces the same effect. That is reflected in spelling of Belarusian, but not of (Great) Russian.

In summary, strictly speaking it is not the current literary norm, but it is good enough for me, as it bears no divergent features of other Slavic languages, instead it is (Great) Russian that (slightly) diverged here.