There is plenty the landlord can control. What this tax does is say the landlord can't just sit on empty properties without penalty.
Heck, the landlord could even work collectively with society to make the area viable for tenants!
The Landlord occupying vast swathes of vacant space in its portfolio is the same as it being vacant. You realize landlords don’t have 1 employee for every employee it’s tenant has, right? That doesn’t scale.
Selling just transfers the issue to someone else.
Making the property more appealing isn’t as groundbreaking a proposition as you might think it is. Every landlord with vacancies in the country is trying to do just that.
Implicit in your entire statement is that somehow Landlords are choosing to keep space vacant, against their own business interests, to… what? Spite the community? It makes no sense what you are saying. They are being punished with this tax while already paying property taxes, utilities, security, maintenance, etc, when the issue is that a pandemic hit and everyone started working from home. Now they should be punished with another tax because the angry masses want to shift the tax burden to them. Democracy at its worst.