I was playing DS, ALL the time during the late 2000's. So HD wasn't even on my mind.
then I bought a PS3 out of hype sometime in 2009. Hated it. Bought a Wii Christmas 2009 and basically I haven't touched HD since. I bought a 3DS and that's what I play now.
I plan on buying a Switch this year, and this is when I will "officially" transition to HD.
So 2018 would be my answer.