Well, "support" doesn't imply "creative control". I doubt a language designer would contract under terms which let companies simply pay to add to the language roadmap.
He likely would let them pay for:
* advice on how to work around the lack of their proposed language feature (as a subset of "advice on how to solve problems in or with the language").
* some influence over prioritisation of the roadmap. If there are two language features Rich was planning to add anyway, pushing one that a paying customer desperately needs up the priority list wouldn't interfere much with the creative direction of the language.
He likely would let them pay for:
* advice on how to work around the lack of their proposed language feature (as a subset of "advice on how to solve problems in or with the language").
* some influence over prioritisation of the roadmap. If there are two language features Rich was planning to add anyway, pushing one that a paying customer desperately needs up the priority list wouldn't interfere much with the creative direction of the language.