What do you mean living and dying by feedback? I have had several sellers emailing me asking why I didn't leave feedback. I deal quite a bit so some do fall through the cracks. Then I get a message asking me to leave feedback by the seller. I think quite a few take this pretty serious.
I think if you have over a 20+ rating with all positives you should be considered fine in my book. I am always puzzled if I don't get a feedback in, when the seller has a 1000+ rating, they want to know what is up with the feedback. It really is getting a bit bizarre but you can use feedback as an advantage when buying from you compared to others. If you have a 100% rating and the other seller has a 99% rating with the same product up for auction and the same price who would you feel more strongly with sending your cash? It's all about perception.
If you already have several hundred feedbacks, what difference doesn 1, 2 or 10 more make? Rarely does an exact same item come up for the exact same price between two sellers to the point where a buyer would even think about trying to choose between two sellers with 100% feedback, one with 425 rating and one with 1269 rating.....
I have never begged for feedback, never have followed up with any transaction on ebay to seek feedback. I leave feedback about once per month in my review of my auctions. The feedback system is a crock of crap as it is where sellers can't ding buyers so of course a seller won't leave feedback for a buyer until he/she gets the feedback from the buyer.
Also, do you really choose buying from someone with 100% feedback versus 99%?
Kirk Daniel tried to leave me negative feedback after he won a $25 item from me and he blew off paying for it for 2 weeks. He ignored my messages so I finally told him I planned to leave him negative feedback mainly just to get his attention(he was too clueless to know as a seller, I can't leave him negative feedback). I filed for the transaction to be cancelled by ebay and they accepted it so I immediately offered the item to someone else who bought it. Kirk suddenly decided to get active on it, tried to deny my cancellation request and suddenly tried to pay for the item. I refunded his attempt to pay me and told him to get lost as I don't have time for his games as I had forgotten to block him from bidding on my auctions. I had no idea he was so hard up for $25. He then left me negative feedback. I contacted ebay and within 2 minutes, they removed his negative feedback as he had no right to leave me negative feedback for a transaction that ebay had declared as mutually cancelled(it appears there are two bugs in the ebay system, one that allowed ebay to process a transaction as "mutally cancelled" before the other party actually responds and the 2nd is that ebay still gave the buyer a chance to leave feedback on a mutually cancelled transaction).
The point is, I potentially was going to have my first negative feedback thanks to Kirk and you can see clearly Kirk was the issue not me. You really put that much credenance into 100% vs 99% when some 99% folks out there might have just strumbled across a buyer like Kirk knowing sellers often have little recourse when a buyer wants to leave negative feedback?