Yes, but you wouldn't know in advance that this codebase you're going to be
assigned to is well-written, or that it does amazing things (unless you're in
its target users group or know the target industry already).
If somebody offered you a job to merely maintain an old, gigantic codebase,
I don't think your first thought would be "wow, I'm going to learn so much
from this!", and there probably wouldn't be any way you could assess the
codebase quality before accepting the offer so you could end up thinking that
eventually. This is how things that you want and that could help you grow can
be vastly different.
If somebody offered you a job to merely maintain an old, gigantic codebase, I don't think your first thought would be "wow, I'm going to learn so much from this!", and there probably wouldn't be any way you could assess the codebase quality before accepting the offer so you could end up thinking that eventually. This is how things that you want and that could help you grow can be vastly different.