Wanting to be able to achieve a result instead of abandoning the game is as much a cricketing reason as it is a logistical one. And I don't think there is anything wrong with decisions made for logistical purposes. It's why I was on board with the idea of a 4 day Test between SA and Zimbabwe. It's when the cricket takes a back seat to money that it bothers me.
The advantage of a 5 day (or 6 day or even 4 day) test vs a timeless one isn't simply run rates. When you limit the game to a fixed amount of time, it gives sides an option of a draw. This means there is more incentive to be aggressive in an attempt to get ahead in the game, because if you mess up and fall behind, you can always cling on till the clock runs out. In a timeless test, you cannot do that. There is no clinging on and fighting till a draw. If you fall behind you either need a massive rearguard effort, or you're done. Cricket improved massively when tests were capped at a certain number of days because now sides were emboldened to actively chase a victory vs playing it safe simply waiting for the other side to **** up first.
The lack of discipline in a timeless test is a great point too. If you have all the time in the world, you have no urgency to actually get through your overs quickly. It's like playing chess without a timer. The introduction of mandatory over-rates with penalties for not complying has been great for the game. It makes it a lot more spectator friendly, and stops it from being merely a battler of attrition.
Reducing a game from 5 days to 4 days doesn't actually add anything to the sport. Sure it may make teams bat more aggressively, bowl more aggressively, and more overs in a day is good for the spectator. But none of these were issues that absolutely had to be addressed. And the fact that the ECB hasn't even cited these as possible reasons for why they are proposing this is already enough evidence that this idea has no cricketing merit.
It's a cash grab, plain and simple. Putting money ahead of the sport. We lose money on the 5th day, cricket no longer earns money to survive but survives to earn money, so we cut the 5th day. It's why domestic cricket all around the world is getting chopped up and shaken up in order to make it more 'profitable', it's why we get T20 leagues everywhere, and it's why smaller nations and teams get no game time. Because the sport is now a money making venture, whereas once it existed simply for the sake of sport with any money earned off it being secondary.
It's sad and disgusting.