They added the MCAS because they didn’t want the Max to be a different type, which meant starting the certification process from scratch. They were able to self certify precisely because it was a 737 type.
Yes - there were many issues that lead to the accidents and you can’t really point to just the one thing; but ultimately it did boil down to a culture at the company created by the environment it operates under.
I’m not defending Boeing here - if anything, I’m more upset at them as they had the engineering will and talent, the political and financial backing to make meaningful changes to the regulatory environment and make aviation safer as a manufacturer - but they chose greed.
Lastly, that’s nowhere near what I said but I can see how you can get to that conclusion. I’m an aviation enthusiast and a Pilot (feel free to go through my post history) - and it’s not a question of weakening regulation; it’s a matter of streamlining ways to get new technology certified faster - it only took 3 decades for the FAA to give the STC for unleaded gasoline etc etc.