That cost will continuously rise up until migration to ipv6 comes out cheaper and enables access to the developing market as well. At which point it is a business no brainer.
Short .com domains actually have an intrinsic value to their prospective owners though, since the domain is the human-readable address, and a shorter address is more memorable to customers. The version of the underlying network protocol is just an implementation detail that the vast majority of companies (basically everyone besides possibly 1.1.1.1 and 8.8.8.8) would happily drop if it became totally unnecessary.
Developed countries will pay obscene amounts for ipv4 space. Just as they do for shorthand .com domains.