I’m guessing you already have tasted the Zwift cycling world.
I can see no reason why you cannot spend all year riding Zwift. If you have certain goals or like the gaming side of it there is a lot to do. 100km/100m rides collecting bikes or kit. If you want to race you can, social you can, training plans etc. I like the different Tour series that pop up now and then. Race them, cruise them, what ever you want.
I have found that I work harder on Zwift than I do outside and I think it is possible to work harder and more frequently inside than outside, especially during the winter.
I use rollers and a power meter which hampers sprinting but I always seem to enjoy the races I enter. I love the rollers, but you need ones with resistance levels I think.
Not sure if I have really answered your post but I’m sure there are cyclist who will spend more time inside on Zwift than outside, and that is due to how good Zwift can be. (for some)
All the best, Ride On (PS I managed to get a puncture inside during a race!!!)