For decades we have hired pilots that had thousands of hours to fly our airliners.
Perhaps, but how did these pilots acquire thousands of hours, if they were not allowed to fly airliners? I can see only four other options:
1) General aviation. GA could be a reasonable source of pilots in the US in the past, but not so much in other countries and certainly not in the future. Considering the latest trends in the economy, GA is a luxury that will soon become totally unaffordable to everyone except the rich. Obviously, you can't hope to recruit all the pilots from just the richest 1% of the population.
2) Military background. Maybe, but the number of military pilots is not so high and will probably decrease in future, due to a general shift to unmanned planes.
3) Small regional airliners. Maybe, but with rising fuel prices and falling real incomes, more people will prefer other travel alternatives like trains and such. Also, the regional airliners tend to become bigger to save costs. E.g. Dash-8 used to be a small Dash8-100, but now we have Q400 that is like 2 times longer...
4) Bush flying in Africa and similar remote places. But would you expect every pilot to start their career in Africa?
To sum it up - the future is grim, and with the way things are going, soon there will be no way for pilots to acquire thousands of hours before they are allowed to fly an airliner. Obviously they won't be going to a widebody right after flight school, but I see no way to avoid 200hr co-pilots on 737's and the like.