Eh, to be honest- skills like spinning, weaving, tailoring are all traditionally not big money makers. They fall into the very unfortunate category of being very time consuming and labor intensive, while still bringing in very little money. (I suspect this is because traditionally, it would be expected that most homemakers would be able to do rudimentary sewing tasks, so you wouldn’t spend money to get someone else to do your tailoring unless you really had to or were very wealthy.) Someone with more historical knowledge than myself should feel free to correct me.
It is true that the spinners Rumple was raised by noticed a great talent within him, and said “he could spin for kings” (haha, I just now realized how clever that line is – in regards to Cora), which would have made him- if not wealthy, then comfortable, at least. However, I think that would have required dedication on his part, if not for actually training to spin, then at least time spent seeking out connections that would allow him to work for the wealthy. Based on the flashback episode of Rumple and Mila’s married life- I think we can assume that he didn’t do this. This is all just sort of… retro-speculation, as I’m sure the set dressers etc at the time weren’t thinking about Peter Pan/the Spinners/etc etc when that episode was shot (even if whispers of this revelation were on the breeze) but looking back at that episode, we see Rumple and Mila living a comfortable life. They have their own home, and it’s cozy. They’re looking toward a bright future. Then Rumplestiltskin comes in with his summons for the war.
He’s ecstatic! Not because of any monetary gains, but because it will give him a chance to distance himself from the reputation of his father, and everything that came with it. At that point, he’s ready to forget the past and throw himself entirely into this new life. That makes me think that he has probably spent some time pursuing this path, and hasn’t been focusing on spinning lately. He doesn’t want to be the boy raised by spinners any more, he wants to be a brave man and a good father and has likely been crafting that self for some time. It’s probably that self (or imagine of a self) that Mila married, perhaps not realizing what it was tied to.
After the war, it was his own reputation that followed him. “He is a coward… just like a father”. There wasn’t anywhere he could move to escape that- and it was at that point in his life that we really see Rumple and Bae in extreme poverty.
"Nothing is easier than to denounce the evildoer; nothing is more difficult than to understand him."