They are not competing directly but their numbers is still important to know the market(s). They are big companies with many customers, they shouldn't be dismissed.
I agree that it's important to size the VPS market, as it directly competes with one of the primary things people come to AWS or GCP for ("How do I host my site?"). As a side comment mentions, I might also include GoDaddy as well as DreamHost and the underlying brands of Endurance, since again so much of the "cloud" is really just people running WordPress "brochure ware" sites.
Having said that, you should realize that some of those companies (GoDaddy, Endurance) are public and even indicate how large they are from an infrastructure sense. Ultimately, VPS and/or website hosting comes down to charging customers $5/month for approximately $0 in infrastructure. The "real" infrastructure money is in either large compute, or "serious" sites. So it is important, but ultimately they'll round towards 0.
Disclaimer: I work on Google Cloud, and have never worked for any of the other companies mentioned.
Having said that, you should realize that some of those companies (GoDaddy, Endurance) are public and even indicate how large they are from an infrastructure sense. Ultimately, VPS and/or website hosting comes down to charging customers $5/month for approximately $0 in infrastructure. The "real" infrastructure money is in either large compute, or "serious" sites. So it is important, but ultimately they'll round towards 0.
Disclaimer: I work on Google Cloud, and have never worked for any of the other companies mentioned.