It is very difficult to suggest a change that isn't already in the game and that new players do not already undertand or pay attention to.
For instance I once requested a buildpower bar that shows the total BP of selected units and their current spending, thinking I could just point new players to it and they would understand immediately.
That was already in the game and I never noticed it, or it just got added at some point and it took me a really long time to notice.
If you already understand that 20 bp on 10 metal income can, no matter what, only spend 10m/s at most (assuming depleted storage) and also understand build priority, any more information in the UI is just clutter. All you need is to know how much BP you currently have selected, which build priority it's on and then quickly look a the top to check your metal income.
I think the real situation is that it's a mix of players don't understand economy, or they do understand to some degree but don't understand their build order is either bad or straight up dysfuctional.
If a player opens with 2+ plates or 1 fac and 6 caretakers, I simply don't know what to do other than to tell them you do not currently have 30+ metal per second to spend and, in lop pot, very likely never will during the entire match. All those players need is at some point, one match, to see one player spam cons and reclaim a bunch, then build a single krow on 4+ caretakers and then they endlessly try to replicate that without understanding how that worked that one time in that one unicorn of a match.
"It sometimes works" ... or so I've been told. Yah, right.
I thought of things like having the commander set to high priority by default and then having a tooltip for new players that states that everything builds slow unless your commander builds it, but that's training wheels and any experienced player will fight back stating that training wheels instill bad habits and are not leading to acquiring a deep understanding of the mechanics.
The same can be said of some level of automation. Some replaces things that are easy to understand but hard to execute (such as skirmishers dodging each other's shots), but some automation becomes a nuisance that the player fights against. What if I intentionally send a bunch of cons to assist something because I know I am capturing a reclaim field and am about to drastically increase my income? Or, what if the team is about to donate me a bunch of metal? I don't want to have to fight automation pulling my cons away when I understand what I am doing and intend on doing exactly what I am ordering.
Thinking out loud, the only thing I think that might work is if cons/cares are pooling more than they can spend, have the beam/fog flash different colors so that it draws attention. If they can spend their full BP, then it's steady green. But that won't stop people from executing 7 cons into 6 caretakers into having all that stall at spending 10m/s.
Some players just don't want to understand. There's that one thing they do and that's what they're going to do every match.