They earn the same 1 gp per day
A PC with a profession is a skilled laborer.
You quote the "Crafting" paragraph, which is about crafting, not about earning gold:
For every day of downtime you spend crafting, you can craft one or more items with a total market value not exceeding 5 gp
A PC makes a thing, but they doesn't get any gold from that activity — they get that thing. Gold is mentioned in the next paragraph "Practicing a Profession":
maintain a modest lifestyle without having to pay 1 gp per day
So it's the same 1 gp revenue for PCs.
Earning gold is complicated
Especially in pre-industrial setting it is more complicated than "craft an item" → "sell it to a vendor" → "rinse and repeat" routine like in videogames.
Unless shopkeepers only pay 70% of the value of the finished product, I don't get how this could make sense.
You made a chair and sell it for 5 sp to a shopkeeper. Now you are going to make 10 chairs and earn 5 gp. But this shopkeeper doesn't need 10 chairs. They agree to buy a couple more, if it would be cheap. After finding demand and supply balance in furniture market, you start to earn 1 gp per day in average.
PHB simplifies all this to fixed numbers, DMs can adjust
The books are deliberately silent about any market conditions. How exactly economy works in the game world is completely up to the DM.
PHB just gives us an example of what 1 gp roughly is:
With one gold piece, a character can buy a bedroll, 50 feet of good rope, or a goat. A skilled (but not exceptional) artisan can earn one gold piece a day.
As a DM you can tweak this in both directions, or leave it as it is, both will be fine. D&D in its core is a game about magic and heroic adventures, not a medieval market simulator.