The main benefit of SaaS to a customer is that theoretically the company should care enough to keep their customers therefore the company should want to keep the product evergreen (functional and features and support).
Churn is such a measurable figure.
Churn is even more expensive for growth SaaS companies, due to equity multipliers.
I remember working for old-school software companies and the incentives were drastically misaligned in the past before SaaS. Existing customers were treated awfully - new customers or updates were where the money was.
Your opinion is a tad too cynical. Although perhaps warrented for twilight products like Evernote getting sold to Bending Spoons. Or the VMware/Broadcom debacle.