We absolutely want everyone using Dark, so jacking the price like this would be extremely counter productive. If we did that, no-one would start using Dark after that.
I don't think this idea will work since there are too many viable options in the marketplace, and people are smart so they will avoid lock-in when they can.
Maybe right now, if the funds are there. But what about in the future, where revenue is required to keep it alive?
These comparisons to Amazon are unfounded, because Amazon is not going to create a blog post one day alerting their customers that AWS is shutting down. AWS was built because Amazon needs it, and people knew that when they signed up. It's not going anywhere.
What about this: pass through infrastructure cost with a wee markup for maintenance/support and negotiate a modest percentage of gross revenue from your successful client companies.
That way you have a low-risk "farm" of potential big hits, and your users have stable costs.