What I'm not convinced of is that it could go much faster than it is right now. Some of the tech debt is from all the way back in 2015. It won't be solved unless we land Chalk and such things and only so many people can work on that at the same time; the speed with which we remove technical debt doesn't scale linearly with the number of people willing to do that work. We are also limited purely by the bors queue, even if we had more people working on it the PRs might not get merged any faster. I want to see concrete evidence (not just abstract arguments) that refocusing will substantially solve the technical (design) debt quicker.
T-Lang work, for example on designing associated type defaults, type ascription, already is focused on fixing technical debt to a large extent. Some technical debt or unfinished things can only be solved with new language design (e.g. I'd be uncomfortable with stabilizing much of implied bounds without where clauses on enum variants, or trait aliases without quantification over traits...). There is other types of debt, e.g. lack of documentation about the compiler -- but that is not something I could substantially help with since I'm not a compiler dev and don't know all the components. Having new designs to implement are also a way to get people into compiler work and moreover, I think that a consequence of less design is just fewer people working on things -- it won't result in all language designers suddenly doing more compiler work.