Can we follow up with what'd be the unanimously acceptable way to notify the user about "buy premium, review our plugin/theme, sale sale sale"? AFAIK right now, nothing is.

We're only talking about restrictions, which will ultimately leave new plugin and theme developers in the dust--making 0 income.

As the one who built The SEO Framework with heart and soul, without ever utilizing persistent notifications, I can expose that 90% of our users don't even know that we have a premium/paid version. Getting that number up to 80% could easily double our income.

I can also expose it took four long years of dealing with debt before I could even climb out of the gutter and think about expanding. Utilizing notifications, like other plugin authors are doing, would surely kickstart a significant income.

I vehemently can't recommend being as pure with FOSS as I have been.

Just tossing an idea out there: Add a standardized and exposed "has premium" button on the plugin/theme page, which leads users to all the information they need.