Yep, they want to shorten it because they've heard people stop playing because they don't have the time. I agree with
@uknsaunders they should let games be proper games even if it means running them till 9pm, but then we're not threatening to stop playing, are we? So why should the ECB be concerned with what we want?
In fact, if they want to stop people who haven't got the time to play cricket leaving, they should replace all the games with football matches, attendance would go through the roof! It would miss the point of an cricket league slightly, but if it gets more people through the doors...