So, I had my doubts about the Order of the Scribes Wizard just as many others. I think giving them the discount for transcribing all spells could've been a strong start for a class that doesn't really have that much to it. But, starting from level 10, couldn't they just... you know, sell their scrolls? They can make them at half the price and time, and following XGE's table for creating scrolls and selling magic items I see some really good possibilities. 

A 4th level spell scroll is a rare magic item that takes 2 workweeks and 2500gp to make, so that is 1 workweek and 1250gp for the OoS Wizard. Rare magic items are sold for 4000gp, half for consumables like potions or this scroll and searching for buyers takes 1 workweek and 25gp. So a lv10 wizard can be making 725gp a every two weeks of downtime if they find a decent buyer (312gp 5sp per week). At lv11, they gain a lv6 spell slot, which means they can amp it up and make 12475gp every 5 weeks (2495 per week!), selling a Very Rare consumable magic item at 20000 gp with an investment of 4 workweeks + 7500 gp for the scroll  + 1 workweek + 25gp for searching a buyer.

Of course, waiting for Master Scrivener (their 10th level feature) can be a drag, but I think it serves its purpose considering spell transcribing costs scale up with the spell level. The OoS just has to worry about transcribing spells lv 1-5, which will most likely be more lower level spells than higher level, before being filthy rich (depending on your campaign use of downtime).

Or maybe, maaaaaaybe I'm reading it wrong.

I think those prices are more guidelines that strict rules. As DM, you have control over the economy of your world. If you want to stick strictly with the downtime rules, you might also want to factor in complications that may result in those activities, which will reduce profit. For example, if a priest accuses you of trafficking dark magic, there might be legal fees involved, and if the player wants to make an example out of the ignorant priest and counter sue the priest for defamation, that may cost even more legal fees. Acquisition Incorporated also have some suggestions regarding running a business, so if you need a way to reduce a player's income, you can find more there.

And, to put a not-fine point on it... its only gold. Gold is practically meaningless 5e, when there's no magical item economy. Indeed, by level 10, most adventurers have already earned enough gold to pretty much retire and live comfortable lives without working for the rest of their days. 

In most other games, gold is realistically just an XP track for equipment. If your DM implements a magic item economy, that's one thing; indeed, it would even interfere with your attempts to make massive profits off scrolls like you are. But default 5e? Doesn't much matter.

To be fair, there was nothing stopping normal wizards from doing the same thing. Imagine, adventuring until level 13, getting 7th level spells and doing nothing but spending your time creating seventh level spell books and selling them to other adventures. Or even make copies of your own spell book and sell that because the cost of transcribing spell books is discounted if you already have the spell written.

If the concern is downtime activities being too powerful for a class, You would hate an artificer. That is basically half of what they do is make magic items. Plus forge clerics, creation bards, the entertainer background, any spell caster over level 8...