There are actually three separate effects here:
Ascension item acquisition
Elo rating deflation
MMO grind length
Boring part
Ascension item acquisition
As the player base expands, a smaller and smaller number qualify for gold, or higher arena.
To compensate, the Devs would have to increase ascension items from other activities.
Or add a grind catch up mechanism that replaces some lower level ascension items ( see grinding).
Elo rating deflation
As new mechanics are added it requires more upgrades to qualify for gold.
To compensate, the Devs would have to increase ascension items from other activities and Hero XP earned.
Or add a grind catch up mechanism that replaces some lower level ascension items and Hero XP ( see grinding).
MMO grind length
As new mechanics are added it requires more time to max a hero.
This actually can impact the Devs cash flow. New players join wanting to play with their friends ( who have team power 3800 ) only to discover how long it takes reach team power 3800.
Magic the Gathering Collectable Card game, World of Warcraft, Book of Heroes, these all have methods for new players to skip all but the last 12 months of game play, or vastly accelerate it, so they can quickly enjoy the latest content and join their friends.
So far the Devs have been distracted by the sheer man hours required for a buyout - successful or failed - and not able to address this issue.
It will be interesting to see if they do address it, and if so, what form it will take.