Three main phases of value as far as investments are concerned
1) The immediate turnaround in the case of a shortage/Nintendo doing the artificial scarcity bit. Some call this scalping, I call this supply and demand -- don't buy it if you don't care to pay the price... not a hard equation.
2) If new in box then over the coming years it might be worth nominally more than original for those wanting one for their display shelves or that only buy new for whatever reason.
I doubt this will become some kind of turning point in a gameplay style, rare and hard to come by accessory (they will likely be making millions of the things) or anything that will seek people find what is now a cult classic like we see in some games.
New in box can also be tricky if batteries are involved -- a puffy or leaky battery is seldom a great look. Such things can be staved off by charging it every so often or replacing batteries but you do also then have worries about solder fun, screen connectors and all the rest.
3) In 30 years it will then be some kind of collector piece. Same, if not worse, problems vis a vis batteries and other longer term failures.
As an investment we get to compare it to stocks, savings accounts and similar. I doubt you will do better than any of those (indeed even current account interest might get you more in some cases). For the particularly amusing case you might even want to compare what buying one and flipping it online will net you vs buying the same price in stocks for a company and flipping them in a week or two if it does get nice and artificial scarcity.
The 30 years later bit is mainly good for those finding it in an attic, finding it in a warehouse, inheriting it from a dead relative or similar.
If I was going to compare it to other games then yeah I would continue either doing the second hand scrounger dance buying things from the clueless/apathetic, from bankruptcy sales, from places with low demand and moving to higher demand regions (tough with cheap postage but can be done), buying "get it out of my house" bundles from bored housewives/spurned lovers to sell off individually, predicting what games (or devs making games that will pop in the future) will be fondly looked back on in a few years but will sell nothing today (or maybe will just have high demand in the future -- there being rather more gamers today than there were in the 80s hence the high price of such things even if they were common enough back then), or that otherwise fall into price traps (speedruns, glitch runs, trophment hunters, lawsuits that make things hard to find, complete collectors seeking those rare bundle games or kid games that sell a few thousand copies...).
