I disagree. Depending on the jurisdiction (in the US), part of the issue is the 10% net loss you end up with. 5-6% on the agent fee(s), another 1% on "mansion tax", in NYS/NYC there is a 1% and 1% transfer tax and 1/2% mortgage tax. Different jurisdictions are less (or more). Throw in more for the lawyer and you're down 10% on the sale. The sales agent fee seem fair for tough markets but even 1% sales agent fees seem preposterous given the market. If the house flips in 1 day, how is that worth 5 or 6%? These days people are negotiating that down to 4% but even that is preposterous given the market.
The problem with the extra 5 or 6% agent fees is: that people dont want to buy/sell as much, because you're effectively losing 20-30% of your 20% down equity on the sale (you'll lose more on the buy with the the 1-2% Title Insurance.) Effectively, you're losing half your 20% down equity.
Of course then...even if sellers want to sell, they dont because they need to bypass the frictional hurdles. Because if you sell and host half your 20% down equity, how the heck do you buy the next home?