I used to work in electronics manufacturing, in a number of different roles, but for this discussion, it would be when I was a test engineer. I used to spec and issue purchase requests for equipment used by the production techs. This was in the mid 1980s. One of the projects I worked on was a switching power supply, that had a number of test points, and the old timer design engineer that I worked with was adamant about using analog multi-meters to monitor things (during the era of the truly great digital multi-meters, as in the Fluke 80XX series). He explained that you don't really use analog meters for getting accurate measurements, but you need to see how fast and how far the needle swings when things are changing during adjustments. Judging rate of change on a digital display is close to impossible, as is how steady a reading is. He did say to make the most accurate measurements, use a digital meter. In the same way, an analog gauge cluster is easier and faster to read than a digital one. You don't read the number (a lot of factory gauges don't even have numbers on them), but just check to make sure the needle is in the right place. It is easy, after you get used to a car, to know where the needles are supposed to point, and can pick up really quickly when they are not in the right place.
My previous car was a 1993 Lincoln Mark VIII LSC. For its day, a top of the line car. It had an analog dash, without even an option to get a digital dash. With the cost of the car from the factory, they could have used a digital dash, but didn't. A lot of the newer, very high end cars, have a screen that displays the dash information, and most can be flipped to display a variety of displays. Almost all come with a default display that is analog. In the case of these cars, there is no cost penalty for putting out a digital read out, yet almost all of them default to an analog display. I just rented a Ford Fusion for a week while in Montreal. It had an analog dash. Has to be a reason for it.
Kostas
P.S. Turbo TBirds had a standard live axle (later on with the Quadra-Shocks). The Thunderbird SC had an IRS (as did all of the MN12 cars, supercharged or not, including the Mark VIII that I had).