It won't impact sales literally at all because people who aren't going to buy it aren't going to buy it.
...i wouldnt be confident in that.
it wont be a ton (like in the hundred of thousands),
but if you want to play it with better performance (as many do) emulating is an option, downloading is easier then ripping it yourself (needing to have an launch Switch and hacking it), so i could see many being like "i already have to download it... ill buy it later, for sure..." and never really buying it.
With piracy its often a trade of between convenienve, quality and price.
music piracy had a steeeeep fall of with streaming, video piracy to ...till there where to many inconveniently distributed places.
Steam and its features (cloud saves, etc) +steel sales helped al lot against game piracy on pc.
I think it will be in the single digits. still a sizable chunk, just seeing how much BotW was emulated and modded.
i generally think TotK, while having the benefit of the huge number of switches out there, wont be much better in sales then BotW. I feel like BotW was a gaming culture moment that a direct sequel on the same console just wont be able to recreate. And people will blame it to a degree on piracy.
(Im not approving or promoting piracy, my statements are meant to be factual statements (meaning its easier to track down a link then original hardware), if im wrong and we have easier methods then that to rip a switch game i am open to enlightenment/correction)
Regarding Switch piracy via ROM downloading and emulation, it's inherently inconvenient. You lose the hybrid functionality and online (or have to find some workaround), you need to obtain the keys from a softmodded Switch or track them down, have a capable enough machine , deal with shader stutters, set up controller support for enabling features like gyro, and so on. Not impossible or even that difficult, but enough to probably stop some folks from going all the way.
The tradeoff has to be worth it. Back in the Dolphin days getting to run Wii/GameCube games in HD was easier to accomplish and it was a marked improvement over the SD image. It was worth dealing with the slight inconvenience.
Now? Well, I've played BotW in 4K. It looks beautiful, of course. But then I booted up BotW on my Switch on the same TV, and at 900p it's not a significantly worse image, it's less of a pain in my ass to connect to my television, pair controllers with gyro, have backed up saves with NSO instead of manually storing my save files on cloud storage, and it's easily portable. So I gave up on the emulation.
That's just my personal experience, but the way I see it - the more barriers there are, and the more acceptable and convenient to access the initial product is, the more infrequent piracy will be.
If its just the same game rendered in 4k, i would be with you, but assuming that they are using mostly the same engine with optimizations and stuff, im confident that many of the modifications (QoL, shading, manipulating draw distance and stuff, gras density,...) can be ported fast (-> in the first weeks to a month or 2), so i am confident that many prefer those aspects to the portability factor (there are many that never undock the switch).
Personally i would not like to sacrifice the portability, the pick up and play mentality (and my split between gaming and computing hardware that i keep up for the most part), so im with you there.
Actually thinking about it...
i have an OG switch, so making a rip would not be to hard... i just dont have the hardware (PC) to do it (13 inch notebook...)... but the prospect of having better LoD rendering, framerate, etc... would be great for a second playthrough.