It is expected that as software matures it gets updated less often, as it becomes more reliable and also gets closer to its feature goal.
Update cadence should go up as new products get released and need to be supported, debugged and improved.
It also depends on a dev team's available bandwidth (i.e, expertise, team size vs demand) to work on bugfixes, improvements and new features.
Also, it depends on what paradigm those teams follow. Is it scrum/agile, or waterfall? Do they aim to release small fixes/additions often or do they prefer to do bigger, richer releases every now and then?
I guess the only way to know is to ask DJI fly app Product Owner about how their dev lifecycle works.