Call me a hairsplitter if you will, but I distinguish between a successful launch and a successful game.
For me, a successful launch would include all of these metrics: preorders, total sales (quantity, not dollars), active players, and sustained sales in the first few months. Some of these metrics we can see, some are estimated, and some have not yet been reported by 2K. My opinion is that the launch has not met my expectations. I'm sure that 2K had some expectations/projections about sales and revenue; I have no way of knowing if the launch met their expectations/forecast. I'm hesitant to call the launch a "flop", because I am not sure how I would distinguish between "unsuccessful", "flop", or "disaster."
For me, a successful game requires time to judge. It needs to receive support, improvements, and additional content. A successful game has a consistent player base measured in months if not years. The loyalty (or lack of loyalty) of the players can't be measured in the first two (or three or six) months after launch. It is simply WAY TOO SOON to know if Civ7 will be a successful game.
I also support the OP and others who want to take a break, wait for updates, and to play other games. I've played some Civ6 in the last week, and some Civ3, and will go back to BERT since I have a personal goal to finish: winning a contact victory with every leader. I'm going to keep Civ7 in my rotation, because I'm having fun.