The thing is, there needs to be a basic 'system' for chains to progress.
At the moment, it's that buyers are proceedable....they have their own buyer and finance in principle, then offer when that offer is accepted, those people can then go and view and do the same. If some people are working like that, it doesn't work if people at the top will only market their house after they have had an offer accepted.
If he system was that no-one marketed until they had an offer accepted on their own, and everyone did this, hen that would be the reverse system and could possibly work......but it isn't the system. It cannot work if neither side of the chain can proceed.
There is a bigger picture and usually no one sale is Independent, but dependent on others. To me, it is perfectly reasonable that buyers must have finance in principle in place and a buyer if they need one. The fact people don't like it, or for some reason can't get their heads round it, doesn't make it wrong.
For some people with very special properties, EAs might be a bit more flexible. And of course, some people are selling and not buying....so they haven't got to go further anyway. And some people are cash buyers too.
But for the standard sort of buyers, who need mortgage finance and who need to sell in order to buy another property, being proceedable i. Terms of having finance set up and also a buyer, makes total sense to the process moving forward. By nature house buying and selling is slow, frustrating, and there are lots of things that can break down before exchange. There would be even more break-downs and delays if there were zero 'norms' and people allowed viewings from anyone and accepted offers from anyone.....far more would collapse because the buyer couldn't get finance or didn't actually I tend to market their property, or did but couldn't get a buyer. Although it can feel annoying, it really is in the best interests of chains proceeding that buyers are proceedable.
I don't think it's a big ask to be honest. People have to get their house ready to sell and market it (if they won't do this, will they ever actually do it or do they want to move) and if they offer without a buyer, most cannot move forward as they wont have the cash to move. It really is logical, if a bit annoying.
As I said before, people just need to think ahead. They have to prepare their property and market it. Once they have done that and oft an offer, they can view and make offers and things can start moving. If by some chance they don't find somewhere to buy, well that's just one of those things and one of the causes of chain collapse. All the causes of chain collapse cannot be removed.