You can look up the congressional hearings from the 1930s I believe on import tarifs. There is some discussion about inferior quality razors imported from Germany. We've talked about these in the past, but I don't have the time to look up the threads.
As far as personal experience, I've seen poor quality vintage razors. Of course, it depends on what you consider as quality, but poor grinds, mediocre edges both qualify for me.
A lot of the early 19th century sheffields are not very good either - even if they have survived without abuse the steel doesn't take a good edge. Of course, there are exceptions and I love them but the technology back there just wasn't up to snuff.