I would attribute any largeness of scale in terms of development time committed, to flaws in management and design approach. The widespread and consistent feedback on the results speaks for itself. I believe they could have avoided a lot of the problems encountered by relying more upon player feedback and testing, and by having better fundamental design choices.
And since Engineering V6 would also be produced and incorporated into the game by Frontier Developments, and not by some mythical competent developer of Elite-like space games, the same is likely to happen again.
Could it be better? Yes. So could the entire rest of the game and I'd rather that they put their effort - however mismanaged and badly designed compared to MythiSoft - into something that has been ignored since initial release.
If you are content with noncompletionist approaches to optimizing new ships you buy...that's grand, but that's a band-aid on the situation at best.
On the contrary I think this is basically the key to the whole dispute. The underlying question is "should players have any meaningful constraints on their ability to upgrade their ship to its maximum?".
If the answer is "no" then the correct approach is just to abolish engineering, and sell G5 modules (no point in offering lower, the downsides are basically irrelevant) as AA-rated in the Outfitting, with some local "engineering" service to pick experimentals at a nominal cost.
If the answer is "yes" then absolutely the engineering system should be encouraging players to think about questions like "which modules are the priority to push to G5" and "how little can I engineer this new ship and still have it fit for purpose" and "having obtained these new materials, what's the priority to spend them" ... which means players shouldn't have the materials they need to just routinely G5 everything - at least not until they've been playing for quite some time.
For the same reason, the dispute between "Frontier need to buff credit earning - 500M/hour is too low" and "Frontier need to nerf credit earning - 1M/hour is too high" player beliefs is never resolvable (though Frontier have certainly picked a side in practice) because they're looking for fundamentally different game experiences.
(The obvious compromise is to have a button in an out-of-the-way place [1] which if pressed gives you full material reserves and 100B credits. There is no penalty for pressing the button as often as you want to, but equally no requirement to press it even once. You can press it, I won't bother, now we're both happy enough with engineering apart from the excessive power gain it's too late to fix.)
[1] Not like "Beagle Point" - just some obscure moon near the bubble where you're not going to accidentally press the button without knowing what it does.