Maserati, Ferrari etc. would add this extra coating layer on top of the buttons and plastic mouldings to give a softer, flatter, more premium look - obviously not realising or minding the long term consequences that we all see.
So far I have removed the sticky coating from the infotainment system in the centre dash (sides and buttons) and the panel and buttons to the left and right of the steering wheel. 3 hours in total. As A.S. Motorsports and others have said, you need a good product, good microfibre cloths and a lot of patience. I wouldn't mind trying the purpose-made solution that A.S. Motorsport mention. At the time, I used "ValetPRO Citrus Pre-Wash Cleaner with citrus oils" which is used as a pre-wash for exterior dirt and grime. I used it undiluted, which gives you sufficient concentration to remove the sticky layer.
Boy oh boy, you do need nerve, patience and persistence! And you need to keep in your mind, all the time, the idea is that all you are doing is diluting and gently agitating that top surface coating layer. You need to maintain your faith that if that is all you are doing, the underlying button/moulding will retain its image and finishing. Start by gently agitating with the solution for a while to further dilute and weaken it. Only then, should you start removing it - it will come off with the microfibre cloth on the buttons; on flat plastic moulding surfaces such as the infotainment surround, I used a small very soft plastic scraper the size of a 20p coin. There should be no expectation or resignation to the notion of going back to a white plastic button! Start by experimenting and honing your technique on one of the less visible buttons and your confidence and technique will grow to tackle other areas.
After removing, you get a decent looking matt finish that, in my view, still looks premium. I finished it off with a coating of matt finish UV protector, which helps with retaining the premium finish. My next jobs to tackle are the window switches (which may need to be removed first as you do not want the solution to enter the electrics) and the climate control panel and buttons.
For the front centre and side air vents, the plastic doesn't look great once you've removed the sticky layer. They seem to be of lower quality plastic than the infotainment system and other plastic panels. I simply re-ordered new ones as they are so easy to replace. However Mark-RetroM's solution could be a more cost-effective solution for the vents.