Transparency and delivering bad news has historically be "bad for business" which is why Nintendo ran PR under this mindset for a very long time
As well as many other companies to this day
Im not defending it but its still pretty much the norm
i do wonder if this is "true".
For example HOI IV was heavily crticized at the start for the lack of several features + several problems. After 1 year of patches + DLC the game had as many plays as it had at launch.
warhammer 2 also has retained around 75% of the playerbase for each DLC despite some problems at the start as well as requiring another game to fully use all the features it has. (the game has 2 years so that is pretty imrpessive)
From my limited knowledge of the video game industry being honest is only "bad for business" if you have 0 reputation of fixing your games, which let's be honest is almost all AAA games.
I have no doubts that if game freak said we have these at launch because we are increasing quality of the pokemons witht he rest being added for free in the next 2 years, i'd bet the backlash would be much smaller. Specially if they made pokemon bank free for those that bought the new game.