Zardnaar
Legend
Sorry but this is wrong.
The market share increased after D&D became popular through critical role and stranger things (and other mentions like big bang theory which made nerd stuff in general more popular).
"When the rules where changed back", with 5E D&D had actually its weakest realease of any WotC release. It did not have any drop off in year 2, but only because year 1 was already just equal to previous editions numbers AFTER dropoff.
Also 4E had its biggest dropoff after Essentials, when the classes where changed back to look similar to previous editions, which made people stopped buying the new Essential products.
Also the biggest reason why D&D decreased its market share was the incredible bad license, which made 3rd party content almost impossible. 5E had with the OGL debacle exactly the same kind of negative reaction, only that there this decision was reversed.
Your argument actually supports 4E damaging the brand and 4E inheriting a decent ecosystem from 3E.
5E even at launch overperformed expectations.
4E had a good launch. We know that goodwill faded very fast. About a year.
They launched essentials 2010 because of 4E reception. It also feeds into Paizos observation of Pathfinder doing very well 2010.
Nothing is in conflict with these observations. 4E being popular at launch them very rapid collapse (about a year).
Even 4E fans admit they struggle to find games whole claiming its popular. Its not that hard to find OSR, Pathfinder or even 3.5 games.
3.0 and 4E are functionally extinct in terms of getting games going.
Very few people dispute 4E had a good launch. Retention more important metric. Once the marketing and buzz wears off you get a better idea how things are going.

