An alternative to ever extending the deadline is a Dutch auction model, where a bid consists of the maximum price you are willing to pay. It's a bit like integrating the snipping bot in eBay and allowing everyone to use it on fair terms.
For example, suppose the current price is $1 and the current winner is someone who bid $2 as their maximum bid ceiling. If I bid a $3 maximum, then I become the winner at a price of $2.
In this model, there is no need for snipping and those who honestly declare their maximum ceiling from the start are in no disadvantage compared to those who frequently update their bid, nor do they overpay.
For example, suppose the current price is $1 and the current winner is someone who bid $2 as their maximum bid ceiling. If I bid a $3 maximum, then I become the winner at a price of $2.
In this model, there is no need for snipping and those who honestly declare their maximum ceiling from the start are in no disadvantage compared to those who frequently update their bid, nor do they overpay.