The common cold is a ton of things, though. We don't bother to develop monoclonal antibody treatments for 1 of 160 common colds or whatever. Massive useless overkill. This virus is different.
The virus behind COVID-19 is so difficult to fight that any vaccine may be more harmful than the disease and the virus may have to burn out on its own, according to one of Australia's top vaccine experts.
https://bit.ly/2weZzfy
Basically he thinks that the virus will create herd immunity before there's time to get a vaccine, and gives no technical details on why it's hard to create a vaccine for this particular virus or this type of virus. Thus, this article seems to contain no info.