For those of you that are wondering, here's what Nintendo said about EarthBound:
"In your letter, you requested that we make EarthBound available for Nintendo Switch, and you also mentioned a desire to see Mother 3 released in North America. While I don't have any info about why the title has not made appearances on any other systems, I will make sure that your feedback is documented, and your comments will be made for our other departments here at Nintendo to thoughtfully consider."
-Casey Cohen
Consumer Service representative