Two factors each narrow the market
Standard landlord programs have value ceilings, and high-value carriers are built around owner-occupied homes. A property that is both expensive and tenanted falls between them, which is why owners sometimes conclude it cannot be placed. It can, through specialist markets, and it is not a quote you get online.
Furnished changes the contents question entirely
High-value rentals are frequently let furnished, which puts the owner’s art, rugs and furnishings in a tenanted property. That is a substantial contents exposure which standard landlord policies are not written for, and it generally needs scheduling item by item.
Liability scales with the property and the guests
Pools, grounds, staff and the people a tenant brings all sit on the owner’s side of the ledger. The liability limit appropriate to an ordinary rental is not the right one here, and an umbrella written to include the property is the normal structure.