Can't they create an API and give developers metered access to their system? A thousand better websites will mushroom overnight with no loss in revenue for them. They can even require the third party site not accept signups or store any data.
In my experience, offering API access is a great way to massively increase developer workload. If they don't want more money, and they don't want to hire lots of new developers, what's the incentive for offering an API?