I disagree. Online commerce has always been very healthy and pervasive almost since the beginning of the web. Payments were never the problem they're sometimes made out to be. "Standards" are completely unnecessary except for the de facto standards of MasterCard and Visa that predated the web.
The rise of adtech is explained simply: many if not most consumers make decisions based on the price of the product, and nothing beats a price of free! If you can offer a product that's free and still make a profit from it by selling ads, then you have a huge advantage over non-free competitors. For physical products, that's nearly impossible, but for virtual products it's quite feasible.
Paid upfront software has a long history on the web, despite the Orwellian revisionism of the App Store apologists who want to erase the past. Even paid upfront software plugins sold on the web have a long history. Web browser plugins and extensions, on the other hand, have tended to be free. This may be the result of most web browsers being free, or included with the operating system. Firefox is free, Chrome is included with Android and free otherwise, Safari is included with macOS/iOS, Internet Explorer was and now Microsoft Edge is included with Windows. The browsers themselves never made a point of taking payments, and so browser extensions were never really designed by the browser vendors with taking payments as a priority. It's kind of an historical accident, but one the browser vendors don't seem to be interested in correcting. Although now for better or worse, Safari web extensions can only be distributed via the Mac App Store.