At least an American billionaire pays some American taxes. If a foreign speculator makes a lot of money they aren't even paying any income or capital gains taxes here.
They are still paying plenty in property tax. From the city's perspective, you couldn't ask for a better resident. Somebody who pays full property tax and consumes almost no services (schools, police, etc).
Why is the city's perspective purely financial? Shouldn't it be driven by the needs of the residents? City residents need housing and the the local business need inhabitants. If you extend your "city" to the limit it would just be a giant physical investment with buildings no one lives in. The city, basically just an investment company would have a lot of money from the taxes and providing minimal services but until that happens the actual residents should drive the policies, in my opinion.
They often pay very little property tax, thanks to California prop 13. Long-time property owners are incentivized to just ride the real estate boom with a vacant building that costs them nothing. The city gets almost no tax revenue, and the neighborhood is crippled in its development.
As a bonus those property owners are politically active and fight zoning reform and development/transit projects to protect aforementioned real estate boom.
They do consume one thing: housing stock that would otherwise be available to residents. Whether or not that outweighs the benefits of paying taxes but not consuming city services is a different issue.
The roads, pipes, cables, buses, firefighters, and cops have to go past the empty house to reach the occupied houses on the other side of it.
Even if the empty home consumes no water, electricity, classroom capacity, bus seats, etc., it still consumes police and fire protection services. Someone else's empty home can be used for crime without worrying about civil forfeitures.
A better resident lives in their home, and cares about what is happening in its neighborhood.
They drive artificial demands which increases the overall price.
At the end of the day, it's not good for the local residents.
It's not as simple as "they're not here thus they're not consuming any services". The resulting effect of sky-high property cost ripples to everything else below it (jobs, transportation, etc).
But they also don’t participate in the local economy and can just blindly vote against anything that impacts their bottom line (e.g. tax increases) rather than having to interact with and see the impact on people who actually live and work there whose lives are impacted by local and regional politics.