Actually from what I understand, Chrysler was bought by MB not merged. Chrysler got the 722.6 auto trans, rear differential , Sprinter vans , Cross Fire, Diesel engine for Jeep and probably a few other things.

I have not read of any Chrysler mechanical parts ending up in a MB.

Unless you are buying a new car from the manufacturer or are the target demographic, you have near zero impact on what they do with future models.

Every car maker had made a good and bad car, what qualifies as "bad" is subject to interpretation.

When Hyundai started to bring cars into the US circa 1985 they were bought by people that would normally buy used cars. Some stretched budgets too thin and left no room for regular maintenance or were poor planners not wanting to maintain the car. This lead to the reputation that early Hyundais were not a good car. In reality there were Mitsubishis built under license and a decent low cost car.

Another point is that quality / features of lesser brands is rising making the spread between a MB and everything else not as wide as it used to be. As the gap lessens, it becomes more and more difficult for MB to justify the added cost so something has to change to reduce costs. And besides, I'd think that most MB new car buyers only own ( RE lease ) the car for sub 4 years or maybe lease a CPO for 4 years. These first two groups likely care little about long term reliability as they don't plan on owning the car that long.