Agreed, these requests tend to be complex (many variables) and APIs are somewhat restricted. But big tech companies should be able to work towards a common API/ecosystem with these players - I would be a user from day one.
This however may just be a matter of time until the incentives align and all of this becomes possible. Eventually, it is my conviction that the web will be conversational first - and typing/clicking will be a secondary mode of action for more advanced queries.
It's different for work, because the company pays for zapier, and people get paid to do work aka use zapier.