The opportunity cost is the intended point. Not only are training times yeeted, it's now more comparatively attractive to invest karma in attributes and skills than on things like spells that have a tiny (karma) cost for huge benefit.
See, I am fine with the concept of a time limit opportunity cost, but I can tell just by looking at that chart, knowing character build options, and the cost of those options that it is going to be too restrictive if the average 7 karma/12,000Y per mission carries over from Chicago. There will be points that cannot get spent in some cases, which is silly.
I don't follow what you're saying in the bolded portion. Or rather, if I DO understand, it's so obviously false that I think I must be misunderstanding what you're saying.
It costs nothing, opportunity-wise, to train attributes, skills, and qualities. It only costs karma (edit: ok, yes. and some nuyen). Spend it and done. Literally that simple. So no I can't imagine any case where you are literally have so much karma you are unable to spend the karma.
Now if you're saying that "maybe you don't want to spend karma on attributes, skills, and qualities. Maybe you got those as high as you'll ever need in chargen, and all you want to do is spend karma on initiating and more spells from here on out". if so: it's still not mathematically correct. The most chargen karma SRM allows you to carry over as fully fungible karma is 5. That means the most karma you can likely have on hand at the first opportunity to spend karma post-chargen is 10-12. You can learn up to 3 spells after your first mission, which that won't cover. And learning 7-ish karma per mission thereafter isn't going to accrue more karma than you can spend solely on non attribute/skill/quality purposes.
The better choice would have just been to alter spell costs if cost for impact is a concern, or you know, just have balanced the base system better. . .(this is the only jab I'll take, I promise!)
Revamping the karma costs for character development was a step too far for SRM's mission. Inventing a between-missions mechanic from whole cloth is acceptable because SRM GMs can't adjudicate between-mission activities without breaking the 4 hour time block constraint or avoiding use of non-sanctioned adventuring material.
Well, it remains to be seen how BGCs will work this time around. But if they work like they did in 5e, a rating 6 focus still works in a rating 4 or 5 background count, whereas the rating 4won't.
Furthermore, you're overlooking negative dice. -2 dice from damage and +6 dice from gear puts you at a net of +4, which caps out your augmented skill still. The rating 4 focus would have only put you at a net +2.
So here is my problem with this.
1. BGC don't exist. So interpreting a rule for a thing that doesn't exist is pointless unless/until it does.
BGCs don't factor into the reasoning behind how the augmented skill rule was interpreted. I brought it up because you alleged that R6 Foci have no value beyond F4, and that's a potential counter-example to a +4 dice cap either way.
2. The logic of the negative dice example doesn't flow for me. I have magic 6 + spellcasting 6 + 2 specialization + 4 spellcasting focus for 18 dice. If I take a negative 2 from to that pool from something how does that alter or change the fact that my pool has still already been augmented by +4?
If we are going to go with a skill test can bear +4 dice after all modifications (both pos and negative) are factored in that is fine, but you have to admit that is just a really sloppy "fix".
Ok.
So rolling a skill test, whether it's an unopposed success test or an opposed test, has the following in common:
The pool is assembled by A+B+C+D+E. A is your raw attribute. B is your bonuses to A, and has a cap of +4. C is your raw skill. D is your expertise/specialization, if you have it. E is everything else, and (under this interpretation/clarification) is capped at +4.
It doesn't seem sloppy to me... it seems the opposite really. Simple and streamlined.