It's not so black and white. The changes mentioned may be a necessary evil when scaling; in this perspective, moving to the cloud makes a set of solutions (rearchitecting) happen sooner than later.
Also, an 8k server is a big unit. Cloud services are much more granular. This is a problem of bare metal - it's easy to overprovision because the base unit is large, and one ends up being happy of having an "overprovisioned" system, when in reality it's money down the drain.
Also, you don't count the management of the 8k server. It may (but not necessarily) be at a click distance; if it is, the management hardware (eg. one from a very famous servers producer) may have a poor software.
There are reasons why, in some cases (of course, not in all or not in many), cloud may be more advantageous than an "8k" bare metal server.
All in all, I think without numbers, talking about metal vs. cloud in abstract, generic terms, makes a poor argument.
My point was that it's peanuts compared to the labor costs it saves. I've worked quite a few places where a single $2-3k server would have saved every employee around an hour a day. In some cases several machines would have saved an hour each.
Every person you don't need gets you more than one person worth of increased productivity due to scaling limits, (see also Fred Brooks, IT and HR - more employees, more support staff).
One of the other aspects is that cloud stuff tends to make very apparent stuff that was always true but often ignored (for one reason or another). Like--that rearchitecture would be a good idea regardless of where you are (because stuff like twelve-factor apps are just a fact of life), they just become more obviously necessary when everyone's always hyping up that Anything Can Disappear At Any Time.
Also, an 8k server is a big unit. Cloud services are much more granular. This is a problem of bare metal - it's easy to overprovision because the base unit is large, and one ends up being happy of having an "overprovisioned" system, when in reality it's money down the drain.
Also, you don't count the management of the 8k server. It may (but not necessarily) be at a click distance; if it is, the management hardware (eg. one from a very famous servers producer) may have a poor software.
There are reasons why, in some cases (of course, not in all or not in many), cloud may be more advantageous than an "8k" bare metal server.
All in all, I think without numbers, talking about metal vs. cloud in abstract, generic terms, makes a poor argument.