I'd rather phrase that as "WhatsApp by comparison is a currently stable, currently popular and growing generic platform implementable and implemented by thousands of companies and hobbyyists worldwide with nothing unique about the company except the current user-base, a (mostly free-loading) user-base which has shown great willingness to flock to the next great thing should this service ever do the wrong moves".
You know... The sort of statement you don't make about 20 billion dollar companies. They should have a more solid footing than being trendy right now. To put it in the dryset terms possible: They have no unique value-proposition.
SpaceX is doing real shit which might make an impact on the future of mankind. To me just comparing them in the same context seems offensive.