In reply to Erick Danzer.

Spot on.

Furthermore, of those 24% that support the Customizer, how many of them also offer an additional options panel and simply support the Customizer in addition to their own option panel?

If you also factor in that Automattic has around 60 themes on the repo, and many themes on the repo are based on underscores and by default are customizer enabled this 24% is actually inflated. I would argue that the number of themes using the Customizer only is significantly lower.

I know most of the CyberChimps themes support both the Customizer (not because we wanted to but because TRT recommended us to support it), and our own theme options. CyberChimps is also the second largest theme company on .org behind Automattic, and we've got nearly the same number of downloads with 1/3 the number of released themes. This alone proves that custom theme option themes are significantly more popular than Customizer only themes even on WordPress.org.

As someone who has sold both Customizer only themes, and a custom theme options panel with drag and drop and a variety of other custom options the Customizer only themes do not sell well by comparison. It isn't even close. Even Responsive by far the most popular theme on the repo has a separate theme options page.

The Customizer failed to achieve major adoption in 3-years, and what adoption it did receive was pretty much forced on us by TRT and Automattic, or slipped in because of the default support in underscores.

The logical and reasonable conclusion to be derived from this data is that the majority of theme authors, and users prefer non-Customizer theme options. The Customizer is applicable for less then 25% of themes currently on the repo, which is beyond a failure in my eyes further illustrating the fact that the new TRT rule of Customizer-only themes in 6 months is entirely unreasonable.