TRUEPLAY ANDROID Legality

This may not change the situation. If users did not own one of the speakers that includes a calibrated microphone, users would be complaining about the need to purchase yet another SONOS unit simply to be able to calibrate their phone/pad or run Trueplay. If you have never used Trueplay there is an operational detail that you should be aware of. The phone/pad must be moved around the room while running Trueplay. If you attempted to do this without using a battery powered unit, there would be a trip hazard associated with the power cord.

Why is there a legal issue with adding a free feature that was never part of the initial product concept?

I'll add another one…

Where would Sonos' development time on tuning better be spent? On autotune technology that doesn't depend on an external device (such as on the Roam) or on trying to implement Trueplay for a vast and ever changing range of Android phones and tablets? It's a rhetorical question. 

There isn’t any that I see, when the feature was offered free, post purchase, back in 2015. It now is a part of the concept for sales being made, but Sonos has made it very clear that an iOS device is needed to enable it, so there isn't any there either - assuming that what I see on the Sonos website is equally clearly stated on any other Sonos marketing collateral including that used by official distributors. 

Another question that is of no interest to the OP, that only Sonos can accurately answer, I would think: Does Trueplay do more in higher memory S2 units than what it does in a Play 1 running on S1? Will a Play 1 do more from the tuning if under S2? Or, more likely, will a latest generation One do more with Trueplay under S2 than what a play 1 does under S1?

Why hasn't Sonos incorporated their Trueplay calibration tool into the microphones built into their speakers?

Perhaps reading some of the threads that have existed in this forum since TruePlay was released might assist you in understanding the challenges around implementing TruePlay would be for Android devices.  There are several. 

The Move and Roam do have auto Trueplay and according the rumour so will the Otimo https://www.theverge.com/2022/8/24/23319989/sonos-optimo-speaker-features-design so it could be coming.  

However, auto Truplay is not a generic tool. Only the speaker running auto Trueplay is equalized.

Another thought strikes me. If Android phone manufacturer X gave assurances to Sonos of a consistent supply of microphone for their phones and (maybe) some development funds for initial and future phone/mic versions, could Sonos say “Trueplay now available on Android“? Other manufacturers and owners of other phones would be rather upset! It might even make the situation worse than it is now. 

Why the hell do you need a Phone to calibrate a Sonos system in the first place.

I have owned Denon, Marantz, Panasonic, Bose systems, and none of them require a phone or a 3rd party piece of technology to calibrate their devices. 

Then sell your Sonos and go with one of the others if you are so unhappy. It has always been the case that you require a compatible iOS device to run Trueplay. If you had done your research prior to purchasing your Sonos system you would have realised this.