You're thinking about companies as monoliths. They are groups of people.
The managers who want remote attestation aren't the people implementing it. They either pay someone else to do it, or they pay someone else to do it. The difference between paying a third-party company and an employee is that employees are more expensive, because the costs aren't amortized over other customers who want the same stuff. Why would they be more trustworthy? Why would they be better at it? Why would it be any less likely to be hacked if you did it at your company than if you outsourced it?