Why did McDavid's rookie card drop? Is it because people were expecting a better season due to the hype? Was offered one for $150 (CAD)... they were released at $250 and were at $300 at one point I think.
Wonder what an Auston Matthews rookie is going to be going for, given it's the first Leafs 1OA in 30 years, and second in their 100 year history.
They didn't really drop so much as they settled.
Most first overall picks/huge rookies peak in price when Series 1 first comes out.
It is hard to project their long term value because it is a unique situation. Crosby is the most recent comparable player and if you look at Beckett's population reports (available on their website) Crosby only has about 2200 graded Young Guns where as McDavid already has around 3300 and there is still probably a lot of series 1 product that has yet to be opened where as cases of 05-06 series 1 are more or less extinct.
Some perspective about other 1st overall centres in the population report, MacKinnon's Young Guns has about 850, Stamkos' has 1150, Tavares has 750. These are the amount of cards sent in to grade, so it isn't a perfect science, but maybe it means something about how many are out there in relation to each other.
Judging by eBay, a raw Crosby goes for around $300-$350 CAD plus shipping. Even if McDavid surpasses Crosby, 10+ years into his career, with the amount of Young Guns that might be out there, I don't think his cards gets that high. Maybe someone with more collecting experience can weigh in though. Anything low numbered from a popular set that hockey fans regard highly I think will go up long term (maybe), but there are so many Mcdavid "rookie year" cards already, I think a lot of it has probably already peaked.
If I wanted to gamble, I might buy some of his Fleer Precious Metal Gem cards. His /50 sold for only around $100 on eBay. I'd rather spend $100 on that than his Young Guns because in 10 years time, how many of those will be out there on the open market, and even if Fleer PMGs aren't as big of a hit with hockey fans as they are with other sports, there'll be a few McDavid completists. If you want to really gamble....buy a Young Guns high gloss and hold on to it for 10 years.
Ultimately, hockey cards are no different than any other collectors based hobby that involve speculating. The moment something is hyped as a future "collectors" item from the get go, but isn't truly limited, odds are it won't be worth as much asp eople are expecting. Only extremely limited stuff or players who no one was looking to collect but broke out of (relatively speaking) nowhere (Say Mark Stone, Ghost this year) are the cards that go up. If you had the foresight to buy 100 Ghost Young Guns in 14-15 and sold them this year, you'd have made a tidy prfoit.