Congrats if you took Van Aert for top3, this dude is something else, with basically no time to rest after the Tour.
Inside one week of the Tour is still fine in general and you can preserve your peak form for this timeframe. Everything after that you will fade and have to start building up your form again. This is also why the Giro/Tour double is way harder than the Tour/Vuelta double. Between Giro/Tour there is normally 5-6 weeks, between Tour/Vuelta 4 weeks, which means that you are plateuing higher to start the build up for Vuelta again. Getting enough rest after a GT is not necessarily the issue; most riders are fresh again after 1-2 weeks. Riding on peak form is another thing though and most athletes are only able to do it for a limited time and have to start all over afterwards. There are some exceptions though, like Valverde, Sagan etc.
Nevertheless WvA is a freak, yes
(...) although for some this is boring sport (...)
It is actually kind of a boring sport, even for a fan like me and regularly betting on it. There are some races which are interesting for good parts (Paris-Roubaix, RVV, GT stages where teams create havoc from the start), but more often than not, it's really boring until the final km's. It's always the same basically: The race starts, an attackers group seperates from the field and then you can watch the peloton chase them for hours.
It's not a sport where you sit in front of the TV nail-biting all the time and in sheer excitement. But when there is some action then, this is a great sport to watch. Not only the sport itself is enjoyable, but also the often beautiful landscape, all the fans, all the drama. The rest of the time you can just let the TV run without paying too much attention and do some other things in the meantime