There's still a benefit in terms of infrastructure reliability. Recovery times are faster, backups more reliable, etc. Basically, vendor managed is better than customer managed in most situations, assuming a competent vendor.

Also, if the cloud systems are architected properly before IT gets hold of them, then they tend to retain their good properties for a long time, especially if others are paying attention to e.g. gitops pull requests.

My current company ended up replacing its (small) operations team in order to get people with cloud expertise. We hired the new team for the skills we needed. It's worked out well.