Does it just involve downloading an app? Not a huge ask...
No it's not a huge ask at all but when you're talking likely viewing figures it's certainly enough to lower them significantly because it takes more than just switching over in the remote and for that you need the entertainment in offer to be enough to make it worthwhile.
For the committed fan, sure they'll do it but for the average punter who may have just flicked over, of course not.
In other words it's nominally free to air but the viewing figures are likely to break some pretty unwanted records for free to air premier league matches
Those without a smart TV or Amazon stick, and that's still a sizeable (the majority) proportion, could stream very easily, but would more than likely then have to watch on the computer or android - which just isn't either as easy or enjoyable as just switching over to another TV channel, it just isn't.
Even YouTube is more accessible to more TVs (via some sky subscriptions or similar) than the Amazon app which can be added but only standard to (most, easily added if not) smart TVs.
There is one reason only why they've chosen to not negotiate with a free to air channel or YouTube and it's to try and get as many non amazon prime members to download their Amazon prime app in the hope they see all their marketing and are subsequently persuaded to pay their subscription fees for prime - pure marketing reasons.