The path to the return of main street is bullying your city council to attach ridiculous property tax penalties for any vacancies for whatever the central business district commercial zone is and not allow land zoned in that fashion to change.
Force the rents and property values down until a competitive market rate is arrived at naturally. Punish the greed that attempts to store or preserve value by leaving things vacant for years.
You’re right but it seems like the exact opposite scenario is usually in effect.
Particularly in the UK, landlords seem stuck in some kind of bizarre logic of “oh, nobody can rent my building, it just has to sit here being worth nothing” and “oh, you want my worthless building, then naturally I’ll need ALL your profit and more.”