If you needed mass ratio 50 in one giant tank you'd be 98% fuel + 2% structure + 0% payload — and structure alone runs 5–10%. Impossible.
Staging escapes the trap: drop empty tanks mid-flight so you stop accelerating dead weight. Each stage carries a modest mass ratio of its own, and the ratios multiply. The Saturn V's three stages were each ~80% fuel, yet together lifted 140 tonnes to LEO out of 3,000 tonnes on the pad.
SpaceX's Falcon 9 reserves first-stage fuel for a landing burn — directly trading payload for reusability, paid for out of this same exponential budget.