One thing is sure, something needs to be done to make cards hold their value better as it's impossible to outearn the expected decline which makes it so that no new players will come in.

What I suggest is the following (Full Article)

1. Create a new Pay2Play Game Mode where players pay some DEC or Credits to enter which is Fun, Easy, and puts everyone on a level playing field.
2. Give Packs as a reward making it an indirect way to purchase them, also possibly include Glints, some SPS or Cosmitic Items.
3. Pay a share of the DEC that is paid to enter to those who provide the cards for this game mode by locking them on Land.