In fact, if anything I think top developers are underpaid in most of the industry. Outside certain organizations and areas, it's hard to break $200k as a developer—even when a senior developer can easily be 2x as effective as a new grad making $100k.
Also, to be clear, the current system is better for probably the whole upper half of engineers. It's not just elite performers who would see cuts if we moved to salary formulas. The problem I see is that humans have a well-documented tendency to hurt themselves if it means they can "punish" others as well: I can people voting for a $100k mandatory salary (while they're making $110k) just to spite me for making $200k.
You seem to believe there are separate stratifications of tech workers that do not have shared interests. Even though I pretty strongly disagree, you're in luck, a union is still what you want. You want a craft union that recognizes something like "senior engineers" as a collective bargaining unit. As long as you can justify that you constitute a real unit with a shared "community of interest" to the NLRB, you can still collectively bargain only with other senior engineers.
I've had a fairly thorough knowledge of salaries at many companies I've worked for (currently the founder of my own company) and I'm not sure what your point is. There was absolutely a large variation in salary and it clearly correlated with two factors: performance and negotiation ability. Why exactly do you think employers pay some engineers so much money? Out of the goodness of their hearts? It's due to measurable impact and differences. I've been places where I was producing more than the rest of the team in half the hours (I was in school at the time).
Your arguments about collective bargaining are precisely why I don't want a union. I sure as hell don't want you (or anyone else) bargaining for me or being tied to any generic salary formula. It's hard for me to imagine that if things were done democratically most engineers would vote for me to make what I do.