"how many songs that are written purely to be commercial are good songs?"

By now, probably many thousands."
what a facile comment, give us some examples.
hilarious, depends rather on what you call a good song, doesnt it?
right,here are some examples of good songs not written with the sole intention of making money, first time ever i saw your face, thirty foot trailer,joy of living, manchester rambler,moving on song,freeborn man. now we all know first time ever became commercially successful , but it was not written with the intention of solely making money.