I dont think anyone has tried to liken ED to minecraft in their respective ways of being a sandbox. A cockpit based, space sim game by definition will be a totally different kind of experience. You need to consider "sandbox" within that context. There is no "building" sandbox in Elite obviously. There is though a space sim activity sandbox. You may like or not the tools given to your disposal but there is plenty as we speak to generate tons of emergent gameplay only if you care to look, alone or in groups:
-Speed racing:
https://www.youtube.com/watch?v=FIm3dfDH7Bs
-Improvised co-op bounty hunting:
https://www.youtube.com/watch?v=NeAmpWRv3jw
(the whole sIsinona series is a great example of pure emergent gameplay in a space sim setting imho)
-Exploration rendez-vous thousands of LY away from civilization:
https://www.youtube.com/watch?v=JvG_pQ0xwrM
-Powerplay group raids into enemy territory:
https://www.youtube.com/watch?v=EDv03eNPn80
-Lending a hand to a stranded ship:
http://www.fenris.co.uk/elite/project/a-tale-of-two-commanders/
-Blockading Khaka at CG:
https://www.youtube.com/watch?v=mARBn2AXDao
I can go on.
I mean, I am sure someone, maybe yourself, are going to dismiss all these with some creative variant of "nah, that´s not it".
But the thing is it is. This is Elite. If you are not happy with this concept of a sandbox or emergent gameplay, a cockpit based space sim related one, then you may want to wait a bit to the future and see what else FDEV has in store for us. Elite has been in development for barely 2.5 years, and it looks it is only getting started.