This actually makes perfect sense, so I'm hoping some rocket scientist will come and explain what are the "devils in the details" that prevent rockets from being built like this.
I'm sure it's easy: some liquids like oxygen and methane are stored under high pressure, you would need an incredibly well built seal and powerful piston.
If it's a room temperature liquid probably there are less complicated solutions like baffles and bladders.
And then you'd gave to over engineer the rocket iself to not break when tipping over, not just the fuel tanks.
And then you'd gave to over engineer the rocket iself to not break when tipping over, not just the fuel tanks.