I don't think django tempating is as bad as you've described but one reason is that a project is long-standing and dev resources are already familiar with it.

I don't think django tempating is as bad as you've described but one reason is that a project is long-standing and dev resources are already familiar with it. A product manager may establish customer demand for an experience on the site that a react SPA would facilitate very well. The org may want to dip its toe in react without throwing out or re-writing vast, stable aspects of the site that may also need ongoing changes.