Because those fonts have different metrics, so they wouldn't have been drop-in replacements, they would have had to re-do all of their branded media.

Loose programming analogy: The free replacements had a slightly different "API" (metrics) that would have required adjusting hundreds or thousands of "call sites" (media using the font), so instead they made their own "API-compatible" (metrically compatible) replacement that dropped straight in.

This is all covered in the documentary short about the font.