Nobrain eco is still a conscious upgrade decision and the only reason it’s feasible to get away with it is that there is no general coordination in 99% of teamgames. Just as nobrain spam can carry you to 1500 in ladder nobrain eco does that in global, but you’re going to plateau there especially when you transition to new styles of maps if you don’t think about why you upgrade mexes in certain conditions.
Astro absolutely has conscious mex upgrades because the map has zero reclaim and near zero expansion mexes, each upgrade needs to be done with peak efficiency through reclaiming needless engie fac, never making too many pgens, not making useless pd, etc. However if you just copy a 1900 astro eco bo then you will never be able to take lessons from it and apply it to diff maps and that’s why there are 1500 astro players that go to wonder or sentons and don’t reclaim a single tree.
Paradoxically ladder is best at teaching smart eco since you actually need to think seriously about the tradeoff of a mex upgrade and teamgames can teach you smart spam since exploiting power spikes or snowball reclaim is the only way you’ll get anywhere with spam in teamgames.