It would be hard to quantify but…
Gambling boots on classic is about ~3x more rewarding in terms of profit. Rare boots have much more value on classic where they are the end game option for all builds. And yes, less affixes makes it easier to get those tri res boots.
But like you said, farming gold on LoD is at least 3x faster.
So it ends up kinda equal in terms of potential profit.
The mistake would be to gamble on classic and the xfer them to LoD on mules. You’d get the worse of both worlds.
So in the end, do it on classic if you actually play classic.
If you play LoD, don’t waste your time gambling boots.
But it’s certainly a lucrative business on classic where you can start doing it day 1 of reset, not competing against bots, and they retain value for much longer than the market is crashing on LoD.
I’d say, gamble regular boots, qlvl 3 (for also a 1/2000 chance to get hotspurs)
They can roll 40res at ilvl 26, which you’ll optimize at clvl 31.
But clvl 31 is only unlocking 20 FRW.
For 30 FRW you would need ilvl 38, clvl 43.