^Yes this, you do have a chance of randomly finding 5$+ commons!
Not just expensive commons, expensive everything.
If you buy bulk that’s a few years old (including holo bulk) you can pull $10+ cards out of it that actually sell. People just leave stuff in boxes either oblivious to its value or cards just appreciate.
There’s no set rotation in Yugioh (for the uninitiated) so every card every printed is still legal to be used. People build old decks and will play them and when you have cards which have been out of print for years still in demand they begin to rise.

Not just expensive commons, expensive everything.
If you buy bulk that’s a few years old (including holo bulk) you can pull $10+ cards out of it that actually sell. People just leave stuff in boxes either oblivious to its value or cards just appreciate.
There’s no set rotation in Yugioh (for the uninitiated) so every card every printed is still legal to be used. People build old decks and will play them and when you have cards which have been out of print for years still in demand they begin to rise.
Based on personal experience though, the chances of holo bulk pulling 10$+ is much rarer than finding some short printed commons due to the rarity factor alone. Holo cards tend to be kept in binders, commons/rares tend to be kept in bulk boxes. If there’s holo bulk, most of the time it is from the premium collection sets or packs with guaranteed holos making them pretty much worthless.
However, what you say is completely true. Anything can suddenly become valuable due to the lack of set rotation. Personal experience though, you have a much higher chance of coming across a common/rare that looks like it won’t be worth much when it is actually worth 5$+ than you coming across a holo of any factor and assuming it’s worth nothing but actually worth a lot.