Even when a company sells maintenance/support/compliance, the incentive is still to put as few actual development hours into these columns as possible, and to pay as little as possible for those hours.
What is actually being sold is a promise, and that really comes from the sales department, not the engineering department. Once the customer signs the contract, the incentive is to do the minimum possible to keep the promise--or better said, break it infrequently and non-egregiously enough that the customer doesn't churn (or sue). So you'll unfortunately still be viewed as a cost-center at many companies if you're working on this stuff.
You are not considering the power dynamics in B2B. The customers get SLAs in their maintenance and support contracts, including monetary penalties. It is also a repetitive business. Bad experiences actually count.
In my experience, if anything development support/maintenance is delivering too much in many cases, i. e. not limiting themselves to fixing bugs, but enhancing functions on customer request.
Maintenance of your software. Can you sell bug fixing of your software? You can sell new features. Of course you will add a line to the contract about bug fixing, and put few poor souls occasionally to fix issues reported by vip customers, but it is not a selling point.
That does not seem to be true in many B2B areas. Software suppliers are selling maintenance and support contracts to their customers. Think ERP.