First whoever told you DJI was a progressive company?

I understand your frustration on wanting a free app (Or even paid) But you have to do a bit of history on DJI and their prior releases. When the releases after the
P2 came, those being the Inspire 1 and P3 Series. DJI did not include any smart functions or autonomous flight functions. They somewhat advertised that these aircraft could do them but "hid" (For those who couldn't actually read marketing BS?) that it would be a SDK and third parties that would have to write the programs for it to happen.
And happen it did, there was a complete onslaught and shootout of third party apps that hit the market. Each fighting for top of the line features, best bang for your buck and product dominance. Some had easy to learn interfaces, some were much more in depth and required a Engineering degree due to feature set

In the end the winner and still champion of the SDK shootout is the well known Litchi App. Some of the others that charged plans and subscriptions folded or developers gave up and moved on. There are free programs out there, there are pay programs out there, the choice is yours. On this, yes DJI did concede eventually and gave us firmware (Inspire and P3) that included the SDK and their versions of some Autonomous functions that were popular but no where near what the third parties had already released...You asked why..here is why.......
The SDK is partly free and partly a charge depends on what the developer is using what part for and level of application(s) So DJI is in the money game, and what company isn't? DJI Sells SDK and while I am not sure how it all works from there I think basically they make a great bit of money from it. Why would they invest their engineers to give away a free product and basically cut their own throat on their SDK program? Answer...they wouldn't.
People already own these third party programs (Like me, I have had Litchi for 4 years (paid once and flown 4 DJI products on it) DJI has little interest in marketing their own software, and I suspect that the latest GSPro was a side endeavor by one of their Apple Engineering staff side who took it upon himself to develop it...DJI gets no money from the free app, nor does that developer(s) he gets a "ataboy" and DJI get's sales because it is available.
As far as market share of Android vs. Apple. I have been flying full size aircraft since I was 14. I have been flying RC for over 30 years and flying DJI since before the P3 days....I know of no pilots (Full Size) that do not use Apple products over a Android based system. Not saying they aren't out there. The Android system is a complete mess and that is another story (But one well known) Apple is a proprietary system and closed. Thus it is easy to market to that segment as you know it will just work. With Android it is a crap shoot at best...it is what it is.
Giving things out for free is not DJI's marketing concept. They know that adding a few features into their new models are marketing and sales enhancements and they sell more given these feature sets. That market, SDK 3rd party apps is pretty much over, those people that use them have already bought them. The newer crowd that are now able to "Afford" DJI products now are just a trickle of what was previously sold. That market was the P3,
P4 and first Mavic. That ship has sailed. You either have been using it for years and already bought what you needed or are a newer pilot that may help with sales and development of the third parties that paid or will pay money to DJI for the SDK. So again if it doesn't help DJI then they will leave sleeping dogs lie and take what is left of the old market share. That is my take on the whole thing I went through it and observed, I might be right or wrong on some things, but it should give you some incite on why things are what they are.

Simply if DJI thought there was a dollar to make, they would make it.
Other than that and PC based systems..I don't like it anymore than you...I hate the "Phone" generation..Thumb flipping fools

But guess what..Litchi covered that in their marketing genius as well.. You pay a small price for their system and you can do it PC, Apple or even Android...I told you they are the King...just get Litchi and be done with it...it is causing you way to much stress over the whole matter (And no, I have no affiliation with DJI or Litchi