If TTG stops producing content then their rights to the IP can expire, same reason Sony had to make new Spiderman and X-Men films every other year last decade.
Changes in leadership and management to Cartoon Network are frequent and often produce a more straight-cut and less innovative direction for the network, the sort of people that institutional stock holders and WarnerMedia management think are the safe options: data analysts, cost minimizers, tough negotiators.
For the above reason and more, many artists stopped wanting to work with the corporation, and new artists are aware of the issues plaguing the company so they also don’t want to touch it. For example, Rebecca Sugar faced a struggle just to continue Steven Universe, one of their more successful titles, but eventually she was forced to wrap it up and leave. Twice.