I think this is largely off the mark for most engineering teams built around roughly-aligned peers.

Sure, if your team is extremely lopsided or unfocused, and e.x. has one person from every discipline, you don't want to cross train everyone into everything else. This is a sign to reorg. Youre not asking your department heads to cross-train to other departments, your PMs/devs to cross train/...

But when you have a 1-to-2-pizza engineering team of e.g. C++ engineers and a tech lead, the lead should absolutely be encouraging this "everyone is a leader" mentality. Anything else means that your tech lead is irreplaceable and if they e.g. get hit by a bus or resign tomorrow you are SCREWED. You essentially are promoting learned helplessness as soon as the subject matter leaves your narrow areas of expertise and the "leaders" are not available to offload decisions to. The best thing a tech lead can do is encourage his workers to make him redundant -- no regular process/decision/... should ideally be blocked by their absence.

As an IC, your manager dreams of you approaching him not like "I have a problem, solve it for me", but instead "I have a problem, here is my recommended fix, how does that sound?". This would be AMAZING. You can then sync on goals/reasoning/approach/... and catch out fundamental misunderstandings on both ends. If one truly is at a fork and someone NEEDS to make a decision (really only if there is conflict as to the preferred approach) then the buck stops at the designated leader. However in most situations your engineers should be empowered to make decisions when they are confident, with review/reflection helping improve/align these decision making skills with their leads/peers over time.

Defaulting to "youre the lead, I cannot-or-willnot walk down the path unless you proceed me" is shit. Sure, when starting off it's great to have an example to follow, but eventually you gotta learn to walk the path yourself (or get off my team).

I want to be promoted one day, and the only way that's going to happen is if I can ensure I have a team of reports who prove they can survive without me (and one of whom hopefully is able to step up and fill the hole).