High St retail vacancies - investor strategy?

Hi just curious as where I live, there's an increasing amount of vacant retail premises along a traditional style high street which was formerly well utilised..there's no redevelopment angle due to heritage controls.

I understand that - in theory - a commercial landlord will prefer to live with vacancies rather than reduce rent to fill the spot faster (or retain a tenant) since this preserves the property's capital value. Further, that loss mitigation may be available from negative gearing.

..However, in this day and age, I suspect most banks will haircut a valuation on paper where the property has not been able to sustain an actual yield. Moreover, a would-be purchaser in most cases would take a similar view where that property has lain empty for an extended period (and others nearby have).

So why would a rational commercial investor seek unsustainable rent/rent growth under these circumstances where there's no redevelopment angle?