Needs autogyro rotor to complete the package. Autogyro is cool but what about an attachable fixed wing?
There have been a few attempts and they all sucked at flying and at being a car. As for water capable auto's, the recent tragedy of the "Ducks" boats in the Ozarks casts some doubt on the idea. Plus, it's all about numbers. How much time will my vehicle spend on the land vs water? How much does it cost? Can I justify it? Is it a convenient solution to any of my current problems?
For 99.99% of the market, the math doesn't work.
I could make a combination motorcycle/dish washer, but it's going to suck at both functions, and be more expensive than buying each separately, and be less fun than having a motorcycle that's great fun to ride and a separate energy effecient dishwasher that leaves my dishes spot free.