It's the least flexible strategy _because_ it's the simplest - as soon as a customer comes knocking requiring data isolation, you have a hard business decision

It's the least flexible strategy _because_ it's the simplest - as soon as a customer comes knocking requiring data isolation, you have a hard business decision to make. It's also a lot harder to extract / deal with a business critical "hot" customer in either direction (either a very performance sensitive customer key to revenue, who could really use their own hardware, or a very bad customer with outsized resource consumption).