It's convenient for cloud vendors to have people believe the choice is between them or having to deal with hardware.
I also worked in ITOps at a medium-ish company and we were moving our colo to Azure, when I left.
Not saying at all that is how it SHOULD BE, but if you are planning on pulling back to onprem (or colo) it should be a concern as it is a hard to mitigate risk.
so while yes, there weren't any fixes for your onprem virtualizers -- there also wasn't any immediate danger as the attacker had to compromise one of your nodes before actually using these attack vectors...
First, having a full level of control can be desirable.
Second, you trade off maintaining firmware levels on hardware and software levels on hardware to managing the way cloud providers build networking and servers themselves (and the cost control as well).
Maintaining your own hardware and keeping it up to date really isn't as bad as people make it out to be. Its not hard to get right either, assuming you can hire any sort of decent system engineer.
Prior to AWS, I was in IT Operations at a large financial services company. I saw the writing on the wall that over time, companies would not want to manage this part of their IT infrastructure themselves. Keep in mind, I was someone who was responsible for keeping the lights on for a decent number of Linux severs.
For an individual company, there really isn't much value in having to maintain firmware levels on all your hardware, patch hypervisors (and try to coordinate all of the maintenance around a fixed pool of hardware), perform months-long evaluation of new hardware before purchasing, test and validate configurations on new hardware, etc. I used to do all of this. I don't miss it either.
Yes, the items above are important, but doing them right is really table-stakes for any reliable IT Operations department. You can choose to spend time getting these right, or delegate that responsibility to a service provider whose main job is to get that stuff right (and recoups that cost across a much larger customer base).