How is the price an issue? It hasn't been with Dash, as far as I know

If masternodes are too easy to afford, people are gonna host them on shitty unstable machines and it will harm the network.
 
We don't need people who are in for a "quick buck", but people who will keep the network strong...

The initial goal concerning the required collateral was to be "accessible" and yet "not too easy to get". No doubt that limit is hard to define, though..

And let's not forget to consider the total supply VS max number of masternodes. The max supply is pretty high, don't forget about it!