@Andrea_R - Respectfully, no; it would not be distribution as defined by copyright law.

Distribution, as a matter of copyright law, specifically involves transfer to the public:

Subject to sections 107 through 122, the owner of copyright under this title has the exclusive rights... to distribute copies or phonorecords of the copyrighted work to the public by sale or other transfer of ownership, or by rental, lease, or lending

Regardless of the opinion of the hypothetical premium theme developer, such a scenario is not a violation of copyright's exclusive right to distribution.