The problem is that everyone's ideal subset of C++ is different because everyone has different requirements!
"A lot of software developers are seduced by the old ‘80/20’ rule. It seems to make a lot of sense: 80% of the people use 20% of the features. So you convince yourself that you only need to implement 20% of the features, and you can still sell 80% as many copies.
C++ is probably a little different. There’s a lot of ways to do things due to accumulated cruft, for example. I’d wager at least a good 20% of C++/STL is to some degree redundant.
Worth keeping in mind: Joel's pulling stats from a very dark spot, located somewhere behind.
In reality, there are common features, and there are rare features - there's just rarely a product manager willing to give up users for clarity of vision.
"A lot of software developers are seduced by the old ‘80/20’ rule. It seems to make a lot of sense: 80% of the people use 20% of the features. So you convince yourself that you only need to implement 20% of the features, and you can still sell 80% as many copies.
Unfortunately, it’s never the same 20%."
https://www.joelonsoftware.com/2006/12/09/simplicity/