I must say, I'm surprised at the recent changes on arena regarding 5th copy rares/mythics. Specifically, when it comes to drafting the 5th copy, or if you have all the rares/mythics from the set, they are giving you gems for each one. 20 for rares, 40 for mythics. This makes the idea of going 'infinite' almost possible. When its a set I know well, I'm barely using up gems and drafting as much as I want already. Whenever I get up to 5k gold, I hit a quick draft for an extra buffer. Add in a few hundred more gems from 5th copies and I think its basically possible now, if you only do 1-2 drafts per day. You still probably need like a 65% winrate, but you needed like a 75-80% winrate before, which wasn't realistically possible. In reality, you may not go 'infinite' but you'll go 'optimal' and only lose a few gems per draft, stretching your money out and making drafts dirt cheap. Below a $1 seems very likely, and maybe even under 50 cents.