Evidence suggests that their engineering teams are either not that big or not that good given how garbage most vehicle UI/software is, and it's a price you pay (mostly) once per touchscreen software design, which will span several models, where as the component + install cost needs to be paid for every vehicle in perpetuity.
If you haven't been there, you cannot imagine how bad most car manufacturer's software departments are. They are big, expensive, and crawling with bad practices. Management usually doesn't have a clue about software, so there's a lot of maneuvering with goals being anything but producing good software quickly and cheaply.
It's a little deeper than this, software for each module is typically provided by a tier 1 or tier 2 supplier according to a spec provided by the OEM. Sometimes the tier 1 or tier 2 supplier is also subbing out the software or stuck with some system on chip that sucks.
So for a made-up example, GM wants to build a smart dash in the latest SUV, maybe Bosch or Continental has one with a SoC inside and their own software hell. OEM works with supplier to integrate, bugfix, skin, and customize. But they don't write it from scratch.
AFAIK, car manufacturers want to bring more software in house as a core competency, which is probably good because the "Tier 1"s are generally even worse at software than them and have worse aligned incentives.
The fact that software is bad is not evidence that it was built by a small team or had a low budget. A depressing amount of high-budget, large-team software is awful.
This is absolutely true, but if you scratch the surface of teams like that what you'll usually find is terrible management more interested in shuffling paperwork and CYA than in quality and excellence.
