This is actually accepted by quite a number of thinkers on the right.
The liberals have the demographic advantage in the short term, but it will shift the other way in the second half of this century.
We won't live to see it however and if they get total power alot of permanent damage can be done.
Liberals are importing their replacement voters, in the form of masses of government-dependent illegal immigrants ... they aren't legal voters now, but they will be soon.