WOW!
Those are some crazy numbers for backs! My personal opinion is that high prices for backs are going to start coming down in the near future. I have been collecting T206 for almost 6 years now and back then I bought several mid-level backs (Sovereign 460, Cycle 460, Tolstoi) with little to no premium added for the back.
For example, 6 years ago, I purchased the following cards:
ALL SGC50 and ALL SOVEREIGN 460:
Pfeffer - $56.00
Hummel - $56.00
Ball - $56.00
Camnitz - $ 56.00
And a Tolstoi, Bill Bergen, Catching in SGC50 for only $80.00
Recently, 6 years later, I had to pay $120.00 for a Sheckard, SGC50, Sovereign 460. That is
Double what I paid for the same backs 6 years ago.
I think some collectors get caught up in what's the hottest fad now. Mid-Level to Rare T206 backs are definitely hot. But, I have seen (here on Net54) many collectors that have bought a somewhat tough back (Hindu for example) only to see them put it right back up for sale when the idea that they may have paid $400+ for a card with a somewhat tough back just doesn't do it for them.
Collecting backs in T206 is tough. Some people are definitely devoted to it, but some just hop in on what's hot only to find out a month later that they would much rather have a mid-grade HOFer than a Hindu back.
I think you will see this latest fad start to regress this year. But what the heck do I know?