So my best investment idea is sealed 1st edition wotc product, and I’ve gone ahead and put my money where my mouth is on that one and bought almost 20 boxes over the past four months and I’ll continue to buy them. I’m bullish on sealed product, specifically 1st edition because it’s a limited product where supply will only ever go down. More PSA 10s can enter the registry as collections and cards are unearthed over the years but there will never be more sealed boxes, every one that gets opened or destroyed makes the others that little bit rarer.
I’ve said before that with boxes you’re invested in the entire set which is great, if a card goes up in value it doesn’t matter if you don’t own a copy if you have the sealed box. With the box you potentially own all the cards, so the box price will appreciate as the cards do. Look at the 1st edition base box, that was about $10k last year, the cards all skyrocketed and now the box is $50k. I believe a lot of PSA 10 1st edition cards from jungle/fossil/rocket etc are undervalued now, as those prices correct over the next few years those boxes are going to grow in value accordingly.
As far as ROI goes could there be better investments? Probably. I think betting on cards specifically though is a lot riskier than sealed product, this is a safe long term hold. I could see jungle/fossil/rocket boxes being where neo destiny is at $4-$5k in five years easily. A lot of the boxes I own have already started selling consistently for $300-$500 more than what I originally paid for them, which at the time was a fair market value.
If you look at MTG, the first expansion made after alpha/beta/unlimited was arabian nights … pokemons version of jungle. The print run on that was 5 million cards in total and December this year would make 24 years since it was released. I know someone that was looking for a sealed box recently and was looking to spend up to $50k for it … he found one person willing to sell after months of searching and they wanted considerably more.
1st edition jungles print run is unknown but definitely way bigger than arabian nights (if I had to guess I’d say it’s about MTG legends print numbers, 35 million cards - just based on my feel of both markets and card/box availability over the same time periods) and it’s only been 18 years since release, but it makes you wonder, where could it be in another six years?
Do I expect $50k? Most definitely not, but it’s clear these boxes are slowly draining out of the market. I look daily and it’s hard to find them let alone at a ‘reasonable’ price. Following the chain of events I strongly believe over time less of these 1st edition cards will be entering the market due to prohibitively expensive or uneconomical box prices because of the reduced supply, meaning less cards hit the PSA registry, and in turn high grade card prices will go up over time because of this (provided there is still demand) as more collectors want the small limited number of them for their sets (there can currently only be a maximum of 37 PSA 10 1st edition jungle holo sets in the world, that is NOTHING!!) … which potentially brings the box into an economical price point for breaking them and grading again, causing those still existing sealed box prices to push higher as more boxes are opened and the available pool gets smaller and smaller until eventually you’re at 1st edition base box territory (not as in price, as in they’re pretty much completely unavailable these days).
So yeah … sealed 1st edition boxes, they’re good IMO 
That said, I think all PSA 10 1st edition holos from everything outside base are underpriced. This is ridiculous:
www.ebay.com.au/itm/PSA-10-Gem-Mint-CLEFABLE-HOLO-Pokemon-1999-1st-Edition-Jungle-Set-1-64/292201192765
So you’re telling me I can buy every single copy (provided they were on the market) of 1st edition jungle clefable for less than $10k? That’s pretty ridiculous, and that’s the case for a lot of these holos - they should be higher than that and I think the price is going to correct as people realise this and pick up cards they need now before they can’t. I and many others have the capital to do something like this (buy every available copy on the market over an extended period of time) on multiple ‘rookie card’ species, it happens in MTG all the time, it wouldn’t surprise me if it starts happening here at some point.
Which will raise 1st edition box prices … 