And this is where rules being skipped over for simplicity probably comes from. Where do you buy a statuette of yourself? We'd assume you'd have a craftsman make it for you. But is the assumption that it would be done the same day?
Because if the craftsman is following the crafting rules in the PHB, it would take him 300 days to complete. Add on the cost of his services, that's a 600gp increase in price.
I can't imagine a game outside of a oneshot where you just...buy these things. Its almost as strange as a character going "can I just buy the lesson to earn a feat before this adventure with a deadline of tomorrow, I don't want to be bogged down by not having access to it."
There wouldn't be an increase in price, because the cost of labor is calculated into the cost of the work. And you've now demonstrated exactly why no one wants to deal with this. Either it is go to the store and buy it, or it is go to the store and then wait a year... and then buy it. Neither of those is interesting. And the "more realistic" version is just a pain in the neck for no good reason.
So, at that point, you might as well just cross the spell off the spell list. Because if you require the crafting rules to be enforced on this and it must be crafted.... then it is never going to happen in a reasonable amount of time, and no one is going to ever bother getting the spell.
This is the same issue even with cheaper spells. Chromatic Orb is not notably more powerful than other 1st level spells, but that 50 gp cost is prohibitive until you get to be 4th level or higher. So either the spell never gets used and is wasted ink on the page, or you handwave the cost. And if you think the cost is part of the balance, fine, charge the cost, but don't then try and make it a side-quest on top of the cost, because at that point you really should just ban the spell and move on.
I'm talking about the sole purpose of getting EB. Nobody does that. Like you said, you get other benefits but you wouldn't have grabbed those options without those other benefits.
EB isn't worth a whole class level. EB isn't worth a feat. EB is like the side dish of a meal. You wouldn't pay a full meal's price for a side dish, but if you get the full meal and the side dish, then it's be worth it.
No one goes and gets Longbow proficiency just for the longbow either, but it is still the best ranged weapon in the game without feats.
And, again, going back to the original point. If it is meant to be defining for the class.... then it NEEDS to be top in its field. Otherwise it isn't class defining. Vicious Mockery isn't the best damage cantrip, but it is the best debuff/control cantrip. It define the bard. Sacred Flame isn't a great cantrip... and it does not define the cleric. And what cantrip defines the wizard? None of them, because they have a selection of equally good options.
The position never was that EB had to be worth an entire class level by itsefl or an entire feat by itself, but that it had to be a superior option to be class defining, and that it is a superior option, because it is sought out heavily.