I just found a spreadsheet I was keeping of ebay BIN prices from 2015...
 

Looking back on this spreadsheet has me laughing, crying, celebrating, and kicking myself. It's the buy it now price of cards I was watching in 2015. Here are some highlights I thought you might enjoy:

1909 E90-1 American Caramel Joe Jackson (PSA 1): $10,000
1909 E90-1 American Caramel Honus Wagner (PSA 3): $3,500
T206 Cy Young Portrait (PSA 1): $350
1910 E90-2 American Caramel Honus Wagner (PSA 1.5): $4,500
1914 E145 Cracker Jack Joe Jackson (PSA 1): $9,500
1933 Goudey Babe Ruth Yellow (PSA 2): $2,250
1933 Goudey Babe Ruth Batting (PSA 2): $1,800
1933 Goudey Babe Ruth Red (PSA 1): $1,500
1933 Goudey Babe Ruth Green (PSA 1): $1,000
1941 Play Ball Joe Dimaggio (PSA 3): $800
1951 Bowman Mickey Mantle (PSA 4): $6,000
1951 Bowman Willie Mays (PSA 4): $4,500
1952 Topps Willie Mays (PSA 1): $450 [I bought this!]
1952 Topps Mickey Mantle (PSA 5): $40,000
1952 Topps Jackie Robinson (PSA 2): $770 [I bought this!]
1952 Topps Roy Campanella (SGC 2.5): $500 [I bought this!]
1954 Topps Hank Aaron (SGC 20): $820 [I bought this!]

I'm glad I jumped on the 50s Topps when I did, but I certainly missed the boat on that pre war. Oh well, what's the saying - spend your time enjoying the cards you have, not crying about the ones you don't.

I'd get upset, but in 2015 I don't have the disposable income that I have now. So I wouldn't be able to afford any of these cards anyway, in either time period.

I wish prices were a little bit lower, but it is what it is. It's a hobby to some, it's a business to others and I wish everyone success in their endeavors.

Now give me a time machine so I can go back to the 1950s and buy all the cards I want!

WOW thanks for sharing but also sad to think the things we missed on should of or could of done, bought, etc
But on the flip side Life goes on and each year we just do what we do in the moment.

It's amazing how big the run up has been in only 7 years. I don't remember what I spent my money on at the time, but I know it didn't have that level of growth. The cheapest card on that list is probably an $8k card now!

Outperforms precous metals!
 

I've dabbled in gold bullion for the past ten+ years, since late 2011. at times I've sold nice cards to buy gold and visa-versa. Vintage cards have consistently outperformed precious metals, hands down, and many other asset classes for that matter. I realize that the last few years have resulted in an unprecedented jump in value, and that a decline is occurring as we speak. But viewed as an investment, over time numerous vintage cards are better than real estate or gold to hold! Now if you bought a lot in 2021, that may be another story...

If you can see 7 years into the future, you can make wise investment choices. That's what this is.

Not to disagree with your overall point, but one can get a PSA 1 Cy portrait for far less than $8k

You’re absolutely right, I missed that on my initial scan of the list. Good luck finding it for $350 though