Admittedly, I see enshittification used colloquially meaning basically “business found a way to fuck over its customers more than usual to increase their profit”. Perhaps that is what you mean by “General enshittification”.
Correct, because the “traditional” definition you outlined with the 3 points is ultimately the same process with the same mechanics and same vectors of force.
the same process
It doesn’t necessarily involve the middle man, who is ultimately the bigger fish that enshittifiers are looking to land. I think that’s relevant. Enshittification’s process involves capturing both a “retail” user base and a business user base and then squeezing both.
Edit. Enshittification is layered and more specific to industries and markets that are not inherently profitable. It starts with seed money being burned for that initial user base and fucks over everyone up and down the chain because the business is not really profitable otherwise. Skimp/shrinkflation is more about squeezing more profit than you are already making.