Correct. Your body will produced chemicals to stabilize your pH. My understanding is no that an alkaline diet raises your pH, but that alkaline intake prevents your body from having to secret harmful chemicals in order to raise your pH.
I believe the same thing about cholesterol. People on very low cholesterol diets force their liver to convert fat to cholesterol, resulting in a release of bad LDL cholesterol. If you eat enough eggs and steak and have a sufficient cholesterol intake to meet your needs, then the liver can rest and do other things, and it doesn’t flood you with bad LDLs.
Your liver will determine your serum chlesterol levels and diet can do little to offset what your liver is genetically programmed to do. That's why statins have been so effective. It's also why family history is so important.