I’m not saying Rowena being a merchant king is unrealistic I’m saying the concept of making a relic by doing the in game equivalent of buying it from the market is not remotely interesting compared to actually collecting it yourself or making it yourself. The parameters you set up in this hypothetical imply that the only way a relic can be made is using materials that are out of reach for the WOL whether due to them being locked away in rich people’s vaults or the WOL simply having no intel on where they are; not particularly unrealistic but also not the only option for collecting powerful relic materials based on how you write it. Remember the original atma’s are crystallised memories of great battle which makes the WOL basically the only one who can collect them
But as for your example if you apply my headcanon to that lore Andreas is a mercantile power himself due to his glassblowing skills so it’s funny you mentioned that particular scenario as that does exactly pertain to him in my headcanons strengths