32bit OID wrap around concerns

One scenario is to use an oid to identify a toast value. As the oid
generation is mono increased within a database instance, it can gets wrap
around after 2^32 generations. After that:
1. GetNewOidWithIndex() could gets unbounded performance as it needs to by
pass already in use values of its own.
2. These by-passed oids are actually usable by other toast indices, but are
wasted. This can lead to further aggravated OID wrap around.

Do we think above scenario is something we shall worry about? Especially
for large databases.

Thanks,
Qingqing