The tyre type is PART of the ride. If you put a runflat on the CX60, you'd be in hospital for a week.
The reality is, you constantly compare the ride quality, but the car you are comparing them too had tyres that are not 'usual'. The Merc ride is actually rather sublime, but the runflats do give it a similar 'jarring' effect of the Mazda over potholes, if you fitted normal tyres to it, like the Mazda has, the ride would be lovely. The Mazda ride is horrible, always has been, always will be until they redesign the suspension, which they will eventually as the cars value is receding faster than Donald Trumps hair line and this is a major factor. Your posts wont improve that, but Mazdas intervention to the widely reported issue will.
I've already answered your second question once on a previous thread weeks ago so feel free to go and peruse that again if you've forgotten.
The title of the thread can be anything it wants to be , similar to the problems threads, there's no law about what is written on it, as you found, when writing on the problems thread and being annoyed with people posting problems. Ironic eh? I was merely clarifying that you cant compare certain things.
The best bit, you turned a little one liner that would have had no real impact to this thread into a big long drawn out discussion, which has certainly diverted the point of the thread, well done you.
This has already been addressed previously a few times in short - depreciation, no dealer wanting it, so I had to stick with Mazda as they were the only dealer willing to give me a decent price and discount on the new car. I also had the silly idea the 'newer' cars would be better (aka internet myth) which I found, they arent

. This was when I realised the depreciated on them is insane because there are so many, and the car is flawed as every review has also mentioned.
What most realise, but some get their knickers in a twist because they don't and they have this buyer defensive ego thing going on, is that I like the car, it's a good looking, excellently designed motor that does a lot right. However, its a massive let down in some fundamental areas, and those that impact me specifically. You don't get improvements to happen by saying nothing. Even as simple has having to wait 50 days to have a dealer workshop slot, that is an insane amount of time to wait to fix a car with a problem that was there on day one..less than six weeks ago. So they need to improve. They won't improve things if stuff is not talked about. You also can't just return a car because of things like ride comfort etc, if you could, I would have chopped it in and moved on to something else and I wouldn't be here writing this.
Why Diesel specifically? Best engine and most affordable setup for an SUV, I'll choose diesel everytime in a car this size, even more so after my experience with the PHEV.