I agree with there being a floor to points costs and a ceiling for that matter. It was something that came up when I used to play Warmachine/Hordes a few years ago. You can move the point costs of units around, but at a certain point, they become too cheap or too expensive for their rules and their role. Too expensive and they are not providing you with enough bodies relative to their rules and points. Too cheap and they become more important as bodies, almost regardless of the rules: holding objectives, blocking charges, laying down buckets of attacks hoping a few get through.
Take a unit like Namarti Thralls. They are priced as elite line infantry, at 140 for 10 bodies with solid statlines and a good special rule. GHB 2019 comes along and at 140 they were a tad expensive for what they did, so they were brought down to 130 This frees up points in a list as a whole and makes certain combos more manageable, hopefully changing the meta.
But what if we went too far? What if they were taken down to 90 a unit, nearly as cheap as moonclan? Now bringing lots of them becomes a no brainer because they have elite line infantry stats at horde infantry pricing. But even taking out their sweeping blades they are still good and can, by sheer numbers of bodies and attacks, they can win the day against anything. Their rules no longer matter so much as how many you can bring, how many attacks you can lay out, how many units you can bring to do different tasks. We've gone to far. By the same token , if we go too far in the other direction, at 200 a unit, and we find that they are too expensive. They have heavy infantry pricing but not the rules to back it up. They are neither dangerous enough, no survivable enough to justify the cost in the list.
It's a balance in short, and it goes both ways.