Book publishers have traditionally published a few books that they thought were of intrinsic merit even though these books were unlikely to make a profit. Nowadays, however, fewer of these books are being published. It seems, ttherefore, that publishers now, more than ever, are more interested in making money than in publishing books of intrinsic value.
The statement 'There has been a notable decline in the quality of books written in recent years' most seriously weakens the argument.