Piracy is the competition.

Companies that recognize that and improve their products and services in order to compete, results in better products and services as well as an influx of happy customers. See valve and steam.

Companies that don't improve and instead seek to stiffle competition through dmca and litigation get their products pirated and services ignored. See how nintendo games are the most pirated on any site that shows stats for such things.

For example, Mario 3 is fucking ancient, how many times does nintendo expect me to buy it? They got my money several times over, and now in order to legally play it on a current platform, it's locked behind a subscription service. No thank you. Besides, I prefer to play platformers with a keyboard. I'd pay for nintendo games again if they let me download to my pc.

Except, what about all the games I bought online for my wiiu and 3ds? Those storefronts are gone, so anything I didn't already have downloaded is gone. If anything happens to those consoles, the few games I do have on them are gone. (i personally never actually had a 3ds or wiiu, but lots of people did and are in this exact boat). I cannot trust nintendo to preserve my purchases, like I can with any other modern digital storefront.

yo ho ho and a bottle of rum.

I think expecting Nintendo do allow people to play their games without being customers is bizarre

If they want those customers they can sell their game on a system that can actually handle it

Because you're presupposing that copyright is right in the first place. Distribution of information has been made free - because of the internet it's the one thing so far where the Star Trek future has been made reality. But intellectual property laws are designed to create artificial scarcity so that one publisher can monopolize a creative work, to the detriment of everyone else.

Fans of various game franchises are not just consumers, but creators in their own right. You have to remember that this delegitimized practice of "piracy" also results in the entire romhacking community.

The bottom line is that free sharing of information benefits us all and produces a rich commons, but intellectual property plunders that commons and produces centralization of media ownership while stripping away our right to be co-creators.