I'd say, based on my experience, that if there's an 'average' big corp, they do targeted TLS proxy: on most or all of their inbound traffic to hosted services a

I'd say, based on my experience, that if there's an 'average' big corp, they do targeted TLS proxy: on most or all of their inbound traffic to hosted services and limited category by category decryption outbound. Yes, they are absolutely concerned about legitimate regulatory and privacy concerns, but they are also concerned about data being exfiltrated, phishing attempts, identifying malicious payloads, etc.