20 yearly is nothing. that's half an hour in an arcade, trampoline park, or county fair. It's lunch for two at a fast food restaurant.
It's a whole lot easier to get the entire family online for 20 a console than it is at 60.
Access to nintendo's virtual library could be worth the cost of admission without anything else.
3rd party support is pretty lame for nintendo so this will most likely be IN ADDITION to xbox live or psn. I couldn't imagine playing Monster Hunter, Call of Duty, Destiny, Halo, etc. on the Switch and likeing it. I think their choice of media may be slightly behind blu ray disks as a dual layer bluray holds 50 GB (UHD bluray can be double that) of data where the biggest nintendo game card holds 32 gb. Without a huge 3rd party library their online service won't hold up to a hard core gamer's needs on it's own.
It'll make a nice addition for under $2.00 a month though!