PRICE for 4 channels is much higher
Well, it IS more expensive but really not that much.
At this time Batronix sells the DS4012 for €1795 and the DS4014 for €1995, the difference there is probably less than what the two extra probes you get is Worth alone, not to mention the two extra channels. Then again, if you know you don't need it then "wasting" €200 is of course stupid.
Whichever model you buy you now get all the options (excluding bandwidth) for free.
They also have the "Economy model", with 2GSa/s and 14Mpts memory, it would be interesting to see a teardown of such a device, if they're TOO the same 4GSa/s, 500MHz, 140Mpts hardware being sold at an even lower pricepoint.