We're all over complicating what is a really simple issue.
Like most things in business, it all comes down to economics. Why should the airlines pay for type rating, or any other training, if employees are willing to pay for it themselves? There's really very little point in taking a moral standpoint on it, along the lines that they should pay because they will benefit. So will you!
I run a business and pay reasonable money each year to train my team - around 8% of our turnover. Some appreciate that, some don't. Some leave the day their training finishes. Some stay for years. If they offered to pay for it themselves, I'd let them.
As long as some are willing to pay for a type rating, and if that's all that stands between them and a job I wouldn't blame them one bit, then the rest of us will have to accept it or go and do something else.
The airlines have long been criticised for bad financial management. On this, I think they're actually operating quite sensibly.