not guaranteed. look at all the big games on DX10 oh thats right there wasnt any.or literally any which made it worth while to upgrade.
i haven't seen one game yet that would make me want dx12.
which is odd as its not that new now and there hasnt been any real buzz about the big games saying and we using dx12. which would have been the case seeing as most big triple aaa games take 2-3 years to develop.
Every major game engine out there supports DX12 or Vulcan. Warhammer, BF1, Deus Ex, Star Citizen, Ark Survival, Forza, etc. are just few games coming out this year that will be using DX12. It's definitely not comparable to DX10, especially now with the Xbox One supporting it as well.