Reasonable people can debate how the pricing should be structured, especially when it comes to online functionality that doesn’t even take a penny of Nintendo’s server budget…
But I don’t think it’s reasonable to expect zero cost at all, when:
Console manufacturers have an unavoidable incentive to sell hardware at a loss (even without factoring in the platforming costs+risks) and make up for it in software sales and add-on services
…and they suffer the reputation hit if any of their offerings are not up to par, in a way that e.g. Windows does not, so they have an unavoidable interest in monitoring and triaging issues with games
…and networked components tend to be the most sensitive and most traceable part of any software system
…and scaling issues tend to be a cross-cutting concern that a third-party vendor who isn’t intimately familiar with the client codebase can affordably help with
It’s just part of the deal you make when you sign up for a walled garden. You get certain guarantees, but only if you pay for the relevant package. You can’t have it both ways – getting the benefit of first-party backing while enjoying the freedom of a purely third-party environment. It’s like a cruise ship that doesn’t let you bring your own alcohol.