Newer generation cards being more popular than older makes card market
So far this is not the case in Splinterlands. Not entirely anyways. Only Zaku, Kitty and Llama is OP. Of the three, really we can only say Zaku and Kitty are more 'all-purpose'.
I'd love to have another max Valnamor, or a max Prince Rennyn, which are both alpha and beta cards. There is still no real match for them in Untamed or Dice edition. But I was taking the analogy for power creep from the Pokemon games, where this is generally true, but there are enough complexity and nuances in the game where the older cards will continue to have good use cases.
Oh.. Cube have self tank heal and scavenge, so unless there is a lot of sneak attack, you are generally okay. Let me show you an example:
https://splinterlands.com/?p=battle&id=sl_a1b5435457a504c9d81ca4248b5c6536
And of course where you can use a Llama (but in your battle with Taraz, Earth Splinter was not an option:)
https://splinterlands.com/?p=battle&id=9818c4522147e7eb0c27f88183ae297eb31c4497
And of course, when you both thought the same, and it becomes a powerplay:
https://splinterlands.com/?p=battle&id=9b385734062bb9853c892c1fc8bfd9beabb3f580
on the last one, the Cube survived the massive sneak attacks from Sandworm (the most powerful sneak attacker of the game)