Greens philosophical adherence to the natural order of things means it has little use for artifacts, and is very good at undoing and shrugging off enemy magic
If you need a really, really bad piece of removal or something other than a cheap flier, then a cheap flier isnt going to be better
Additionally, you can find galaxy foil versions of these lands in Collector Boosters
That said, the fact we saw such a drastic move as canonically eliminating the majority of Planeswalkers from the lore suggests a reduction in perceived future demand for the card type, to say the very least
Imposter Mech is already a pretty sweet card for blue decks, but I like it copying a powerful commander controlled by an opponent, and you can reset it periodically with your blink shenanigans
Even if the pods gunning for you for some reason, you can usually divvy up the end step trigger in a way thats not that detrimental to you