I think they made the right decision -
The money the ECB got from Sky was invested directly in the game, whereas providing a second-rate coverage for cheapskates wouldn't necessarily have done anything for the game - no guarantee, anyway!
Also - Sky are prepared to put the money in and invest in good production values, clear their schedules completely for uninterrupted coverage over long periods.
Whereas channels like the BBC or Channel 4 will only ever see Cricket as a minority interest that will be shunted out of the schedules and starved of funding!
In the end it was a no-brainer!
[even those who can't afford to have Sky can go to pubs,clubs and sports bars etc. to watch - win/win!]