I agree, but I think that input is limited to unopinionated information about the technical impact or user-facing impact of each task.

I don't think it can be said that senior engineers persuade their leaders to take one position or the other, because you can't really argue against a political or financial decision using technical or altruistic arguments, especially when you have no access to the political or financial context in which these decisions are made. In those conversations, "we need to do this for the good of the business" is an unbeatable move.

I guess this is also a matter of organisational policy and how much power individual teams/organisational units have.

I would imagine mature organisations without serious short/medium term existential risk due to product features may build some push back mechanisms to defend against the inherent cost of maintaining existing business (ie prioritising tech debt to avoid outages etc).

In general, it is a probably a mix of the two - even if there is a mandate from up high, things are typically arranged so that it can only occupy X% of a team’s capacity in normal operation etc, with at least some amount “protected” for things the team thinks are important. Of course, this is not the case everywhere and a specific demand might require “all hands on deck”, but to me that seems like a short-sighted decision without an extremely good reason.

In my 30 years in industry -- "we need to do this for the good of the business" has come up maybe a dozen times, tops. Things are generally much more open to debate with different perspectives, including things like feasibility. Every blue moon you'll get "GDPR is here... this MUST be done". But for 99% of the work there's a reasonable argument for a range of work to get prioritized.