there is a difference between being cautious and paranoid.
so far there has been millions of bitcoin keys created and trillions of dollars worth of bitcoin have been transferred around and to this day there has not been a single case of bad RNG coming from the good wallets like bitcoin core or electrum. the cases were from new, shady or weak codes or services such as blockchain.info, javascript base websites and wallets,...
that is why people aren't really looking for alternatives, specially when that alternative could take an hour of their time and still not be safe.