An interesting thread and it would appear that the lack of FO's is creating a problem. If the reality is that FO's are leaving in significant numbers, then surely there should be some incentives introduced to make them stay.
I for one believe a possible answer could be in bonding FO's for a period following the company paying for the type rating training. The FO would then be less likely to leave the company if they were going to have to pay out a substantial sum of money to "buy" their freedom from a contract.
Additionally, this scenario would give low hours guys like me the opportunity to get a foot in the door without having to pay through the nose for a type rating.
The company would in effect be buying my loyalty. And I'm sure that loyalty would prove to be a lot more cost effective in the long run than paying a captain to do the job of an FO.
I suspect the problems described on this particular thread are due to a lack of forward planning by the bean counters who are only looking at the profit margins in the short term. Perhaps a sound ten to twenty year business plan would alleviate situations such as this developing in the future.