Compatibly they are a green company. That doesn't mean they can't do a lot better. Doesn't really matter how recyclable the iPhone is, the fact remains that the faster an upgrade cycle is, the more CO2 that is put out in creating the replacement device, the more environmental destruction is caused through the mining of materials for the replacement device. Then you assume that all devices actually get recycled, the realty is that they don't. Many devices get incinerated/dumped/whatever - all of which damage ecosystems etc.
And what - do you know what my diet consists of or something? Have you heard of the concept of doing two things at once? Yes thats right, the world can both move towards consumption of food that is less environmentally damaging and also reduce the effects of discarded devices and the upgrade cycle on the environment. Just because something is damaging to the environment and something else is less so doesn't mean it is a good thing to ignore one.
https://www.getorchard.com/blog/iphone-environmental-impact/
Ensuring devices remain useful for the longest period possible is important environmentally and you'd be a fool to argue otherwise.
My interest in keeping A5 devices useable until it is no longer possible is for a number of reasons.
1. The environmental (as I have already discussed) impact of around 40 percent of installed iPads (A huge number) becoming obsolete due to a lack of security updates and therefore discarded of, and then the amount of energy and emissions caused through the creation of replacement devices.
2. Apple giving proper support to users of iPad Mini 1s and iPod Touch 5 users who purchased devices around 6 months ago. (And still to an extent iPad 2 users from 2014) Apple's greed in keeping these models for sale is part of the reason so many people are still on A5 devices, and thus those who purchases such devices should be able to update their devices for as long as it is technically possible to run even the most stripped down version of iOS on their devices. 12 months of support is not good enough for premium products. Otherwise apple should have sold the iPod Touch 5 (which was by the way their premium iPod till well into 2015) and the iPad Mini 1 (And even the iPad 2 back in 2014) clearly stating that those devices would not be essentially become obsolete less than a year after purchase.
3. While you find A5 devices 'obsolete' and whatever, that is a personal opinion. Many people find A5 iPads more than usable still, myself included. iOS 9 may have slowed them down, however for many these devices remain more than useful, thus if it can be done, there is no reason for Apple to arbitrarily cut them off from a very basic version of iOS 10.
There is plenty of Apple software that the majority of Apple users will never use. What about the effort put into 'Move to iPhone for Android' or Apple Music for Android. That is also 'At the expense of the platform'. Again Apple was more than happy to take large profit margins on older devices, so perhaps some of that money can go into further support.