Is there anyone else out there still doing waterfall and estimating in hours and everything is just going fine, or am I just that lucky? I work on a small prof

Is there anyone else out there still doing waterfall and estimating in hours and everything is just going fine, or am I just that lucky? I work on a small professional services team customizing a couple of our products for our customers. A few times a month we get a request for an estimate to add a new feature or workflow. We do a high level customer requirements doc, discuss it as a team, the seniors from each area (design, development, qa) each provide an estimate in a range of hours. This all gets wrapped up into a final price to the customer. If they approve it, we dive into detailed design and have them sign off on the result. Then we go into development for weeks to months, qa, and then release. Our processes really haven’t changed in over 20 years. We’re constantly ranked as one of the most productive teams, and get high scores on our post-project surveys from our customers.