Why do most Brokers/Agents refuse the 'Exclusive' challenge despite holdover clause?

[Account Closed]

Nowadays all listing agreements - even open - contain holdover clauses with decent timeframes so that sellers can't get away with circumventing commission due to buyers the agent found.

So why is it that most agents still use the holdover argument to evade settling for anything other than exclusive right to sell?

When I used to sell way back in the day when i wasn't yet an agent, despite the 'Principals Only' warning boldly plastered all over my FSBO listings, agents nevertheless lined up at my doors with the usual pitch even when notified in writing to cease communication, still wanting ERTS, throwing fits and all, sometimes even disrupting my open houses under the guise of bringing 'buyers ready to sign' that were 'on their way' yet never showed.

Granted over those years, there were 1 or 2 out of dozens upon dozens agents who were up for the challenge to compete with my own offers, but most others were just too greedy or whatever and just would reiterate the holdover clause like parrots, pretending to not understand holdover clause is why exclusive agency without right to sell remains a viable compromise and formidable challenge to truly measure up to.

have you as investors (and/or as agents) ever had similar gripes with stubborn/aggressive agents who yet weren't up for the challenge competing with the owner(s) themselves to find the best offer that successfully closes?

or do you yourself an agent either take only ERTS or lose the listing altogether, no matter how stern the seller?