I am guessing that this is a precursor to what will be happening in "Sims 5" and they want us to get used to it now. Also, once that new game is released, they might want to move Sims 4 to a store content set up, rather than more packs, and then the cart might connect seamlessly to the store for instant downloading of individual items, something like in Sims 3. It is just a guess, but either of those scenarios would be an incentive to introduce a cart.
I think the pulsating effect is the biggest mistake, and to not entirely remove it when they know it is harming people is unforgivable. The only reason I am still able to play is because of a mod that removes the cart. So I do completely understand that anyone who is not on a PC and cannot use mods might just throw in the towel, out of necessity. As well as principle.
It is a huge mistake for the company to not address this situation openly, and to refuse to communicate their rational for keeping the cart in the game. It was also a mistake to call it a feature, when it is plainly advertising. Whoever came up with the idea, and the approach, does not understand marketing.
If EA still had a monopoly on a people-type simulation game, I could comprehend them standing their ground and toughing it out, because they would have a real hold on the vast majority of people. However, to make such a move now, when several viable alternatives to the Sims franchise are in the news and set to release in the near future is more than foolhardy. EA's next offering will not be ready to directly compete with the new simulation games, all of which have features never seen in the EA Sims franchise. Features that look really good. This is NOT the time to drive your base into the arms of an up and coming company, EA.
It is not too late for EA to reverse course, if they hurry. But time is running out. Once people stop playing, and find other things to do with their time, they will not feel the need to look back. Especially with a new shiny grabbing their attention.
I want to continue to play Sims 4 because I only came on board when Henford-on-Bagley released (Sims 3 never had bunnies), so it is still all fresh and new to me. I have been buying everything on release day, just because of the excitement and thrill of new content. But after this fiasco, I will be sitting back without updating, to see if anything else might threaten my continued playing of the game. I will not risk losing what I have right now. Only when I am sure my game is safe will I update or buy the next content offering. What a buzzkill.
And the chances of me moving on to Sims 5 is looking dimmer each day. I cannot afford to invest in a new game that might "explode in my face," at any moment. I have loved the Sims since Sims 1, but EA has managed to kill all my excitement. Sigh.