@FtXCommando Even top players will skip marginal improvements, if the benefit to implement them is too small or the cost too large. Take hotkey layouts as an example:
The hotkey setups that pro players use, and I mean all of them, are likely suboptimal. Why? Because you can't assign the hotkeys you would actually want due to hotkey overloading not being supported.
If I put e.g. the transport units command on the "T" hotkey I can't assign the launch tac missile command to also be on "T", even though the units that can shoot tac missiles can't transport and the units that can transport can't shoot tac missiles.
The result being that there are like a dozen premium hotkeys on the left side of the keyboard, but if I want to assign hotkeys to everything, as you should for optimal play, you have to use keys like I, K and L for the lesser used stuff. That's just bad.
Afaik, modding the game would actually allow hotkey overloading, but doing so is nontrivial so nobody has done it yet.
The result? Even though there is a small improvement to be gained here, no pro uses an 'optimal' hotkey layout as the cost for doing so would be sitting down for a couple weeks and coding it yourself. That's just not worth it.
The ASI mod could be in a similar spot: If you have thousands of hours in the game it will take you weeks or more to adjust to new icons. And you'd do that for an, at most, small gain, so why bother?
The difference to the target priorities mod is that the target priorities mod can be implemented into your gameplay gradually: If you have it installed, you can completely forget about it until you need it, and even then, none of the old gameplay is changed if you don't want to use it afterall.
An icon change on the other hand can't really be introduced gradually: You either change the icons or you don't, and every time you change a common icon it will be very jarring to players who have years of experience with the default icons.
So, in contrast to the target priorities mod, you can't just forget about ASI and as a pro it will probably have a negative impact on your gameplay for weeks until you get used to it.
(This is one possible explanation for why some pros use only the icons for nukes and so on, as they are probably where ASI is strongest, hence the highest gain, but they also appear very rarely, hence the lowest cost.)
((Also I'd argue that using the target priorities mod gains you more than the ASI mod does, as the former allows you to do things that were literally impossible before, which the latter doesn't))
Regarding a mod's performance in non-tournament games: Consider a mod that, through magic, gives you an extra 200 mass on Astro Crater at the start of the game. I think it's fairly obvious that using this mod would be straight up mandatory if you wanted to be the best Astro player there is, while benefiting you not at all in tournaments.
Also note that I said team games, not casual games. There have been team game tournament and hopefully there will be more in the future, but as of this moment there certainly haven't been enough of them to definitively say that literally every setup detail that's optimal for 1v1 tournaments is also optimal for team game tournaments. In fact, I'd be very surprised if that were the case.
Lastly, saying "time will tell" and "the better players will in the long run" is of course correct. I just don't want to wait until 2025 when a new generation of pros all use ASI 3.0 or something. I want to figure out what's optimal now.