Anecdotal
"dirty":
- When my father was a child, the waste disposal service was so well paid, that it was even attractive to work there for totally overqualified people.
"dangerous":
- coal miners, dangerous good truck drivers,... could works often elsewhere
"difficult":
- that is not a problem at all. Difficulties are challenges and people like challenges

Perhaps there would be problems in Western Europe with home care of old people, which is now often done by eastern Europeans under really bad conditions - and e.g. in Poland similar jobs that are done by Poles in Germany are done by Ukrainians in Poland. OTOH low paid work becomes more attractive with a basic income, and there is the human mind.
When there are problems, solve them. I think the next big technical development will be a much increased use of roboters in everyday live. When some unnice jobs are currently done for very little money, there is little incentive to use capital to improve productivity in such branches. When you can't get cheap labour to do X, there will be an incentive to invest capital, and creativity into doing X better.

Der Amerikaner ist die Orchidee unter den Menschen
Volker Pispers