Is it lazy to rerelease old movies onto Blu-Ray for full price with no new content instead of making brand new movies?
Also, it's not instead of, it's in addition to. Nintendo porting Mario Kart 8 to Switch allowed that team to make a new IP in ARMS, porting NSMBU allowed that team to make Mario Maker 2
Same goes for other publishers. Porting old entries in Mega Man, Resident Evil, Street Fighter, etc did not prevent Capcom from releasing games like Monster Hunter World, Resident Evil 7, Devil May Cry, etc.
Releasing previous gen games on a current platform let's people replay games they enjoy or play games that they are interested in but never had the chance to play.
It's still diverting manpower away from the creation of fresh new content though. A company ultimately only has so many employees and studios.
How much manpower/resources did games like MK8D or NSMBUD take away? Like I said, both of the teams also released brand new games a few months later so best case scenario we are looking at ARMS & Mario Maker releasing slightly sooner if those ports weren't released.
What is better, Mario Kart Deluxe in April followed by ARMS in June or just ARMS in April? How about Super Mario Deluxe in January followed by Mario Maker 2 in June or just Mario Maker 2 in March?
You also said people are too dumb to know they are getting ripped off but I'll give you my reason for rebuying those 2 games. I bought a Wii U in Spring of 2014, NSMB was bundled and I also picked up MK8 along with it.
4 years later i no longer own a Wii U but my 2 oldest kids are now 4 & 6 and are really getting interested in gaming and always want to play with me so I picked up MK8D & NSMB because those 2 games are a perfect introduction to gaming for young kids and we can all 3 play together at the same time.
Would you say that I was ripped off by having to pay full price to for 2 games that have given me dozens of hours of fun with my kids and let us bond over a common interest?