I spoke to 5 separate vets about this and they all disagreed with your statement.Once you have had a case of parvo in your home it would be wise to do a thorough cleaning and there is a sticky at the top of the health forum with some basic guidelines. Also, it would be very unwise to bring another young puppy (or an elderly dog with an aging immune system) to your home for at least one year. Parvo is highly contagious and lives in the environment (dirt, carpeting, upholstry, floors, ANYTHING the infected dog had contact with) for at least one year, maybe longer.
See, I fostered two puppies for a rescue group, both of which came down with parvo within 4 days of arriving at my house. It has a happy ending for them, they both made it and went on to be adopted.
I was supposed to be bringing my own two puppies home 2 months later and was very worried. I spoke with the vet I work with and she if I had bleached the house not to worry. Apparently Parvo can only live inside for about a month anyway, so if you bleach and then wait a month you are more than fine.
I spoke with another vet that my mom uses and he said the same thing. His only extra advice was to keep them away from where the parvo puppies went outside but that he thought by two months it probably wouldn't be a big deal as long as I had cleaned my yard.
When I brought my first pup home she ended up with a 104 fever 5 days later and of course my first panicked thought was "Parvo!". It happened at night so I rushed her to the E-Vet. I told them the situation with having had parvo puppies in my house and they asked if my girl had any vomit or diarrhea. She didn't so they said it probably wasn't parvo (okay, I knew this logically but when it's your own you don't necessarily think clearly) but would test anyway. Well, it wasn't parvo, just a bad UTI and she went home the next day almost 100% better.
During the time with the e-vet though I asked the admitting doc, the doc who took care of her the next day, AND the one doc consulted with another just to make sure. All three of those docs also said that since it had been two months at that point and I had bleached they had absolutely no concern that it was parvo, even before the test results came back.
Take all of this as you will but that's 5 separate vets who all told me not to worry as it had been two months and I had bleached well. Each vet (minus the three working together) was unaware of what the others had suggested and each gave me the same answer. One of my pups is also a black/tan breed which are for an unknown reason more susceptible to parvo than the average dog and still no parvo issues. They've been here for almost 3 months now and are doing just fine and even using the area that parvo puppies did.
Before panicking people that they can't get another dog for a year I'd suggest they talk with their own vet or multiple vets and see what they say.