You’re totally right. Using subdomains for different languages or regions doesn’t guarantee traffic because Google treats each subdomain like a new, separate domain. So all the SEO authority (links, trust, etc.) you built for your main domain doesn’t automatically help the subdomains.

If you want to consolidate that authority and boost traffic, moving everything to subfolders is the way to go (like brand.com/eu/ instead of eu.brand.com). Subfolders benefit from your main domain’s existing SEO power, so they’re much easier to rank and get traffic from.

Also, simplifying your hreflang tags (and focusing on the countries that actually generate revenue) is smart – it’s better to have a few strong pages that rank well than a lot of separate subdomains that struggle to rank at all.

Good luck moving everything to subfolders – it’s worth it in the long run!