If the person you pay is an employee you do not get the external guarantee, nor would you if you pay someone to maintain a server that is yours. The big email

If the person you pay is an employee you do not get the external guarantee, nor would you if you pay someone to maintain a server that is yours. The big email providers do not really provide a worthwhile SLA to most customers AFAIK. Do they cover the cost of business interruption if your business is heavily dependent on email, for example?