Authorship and citations are basically academic currency, and as such have undergone inflation just like real currency. Professors get their name on a paper as a form of payment for future or past services to other professors (often related to funding). There's just no incentive for anyone to stop this as far as I can't tell, and appealing to ethical conduct in authorship and citations is not enough.
Currencies don't just undergo inflation for no reason. Central banks create that situation on purpose to discourage saving.
(Another, more-natural (Austrian), cause of inflation is a contracting economy so dollars chase fewer goods.)
If understanding/knowledge is being accumulated by a field the new publications should make those that they cite even more valuable, not less like in the case of a fungible currency.
That sounds like people who are not Euler engaging in dubious behavior.