According to the Cambridge dictionary, there are a couple of variants depending on your dialect:
- "to make something else seem better or more attractive when combining with it" - e.g. "Strawberries and cream complement each other perfectly."
- "to help make something or someone more complete or effective" - e.g. "She used photographs to complement the text of the news story. "
The only way I can make any sense of your words is to assume you're trying to argue that two competing but interchangeable services "complement" each other when used simultaneously because that might allow a customer to mitigate risk in a similar fashion to a multi-cloud setup. That's a pretty big jump to make from what you've actually said though and would really need further explanation for anyone to understand.
Substitute goods have negatively correlated demand, while complementary ones have demand that positively correlate. A simple criterion, at least in theory. You will buy more ketchup when you buy more franks, but you will buy fewer hot dogs.
And it's also close enough to the MBA definition of complement (of "commoditize your complement" fame).
Classic VM hosting is a dead end anyway. Customers are shifting to the hyperscalers wherever they can, if only to reduce the headcount of their IT departments due to acounting wizardry making it worth it for the stonk markets even if the cloud costs more in the end.
And then, there aren't that many alternatives to VMware, and none of them (bar OpenStack) as comprehensive.
As long as Broadcom manages to squeeze enough out of the large customers who are vendor-locked too hard over the next 3-5 years, it'll be worth the money for them, and chances are the gamble pays off, with a small trail of extremely large customers paying for a decade until they can get their internal chaos sorted out to migrate off.