1. Not every one would work to pay taxes, when there is a way to not work and still get paid.
2. Lesser the number of people who work lesser the pool of money to share among the remaining.
3. Those who still continue to work feel cheated all the time to be working and making up for everyone. While they push insane hours to make a living, punished all the time for earning, endlessly being asked to pay for others, or be called greedy and evil otherwise.
4. Mass exodus of people follows to places where there is a decent rewards in return for work.
5. Ecosystem as a whole has endless iteration of fewer and fewer contributors, and more and more people who think are entitled to free cash. At some point it all collapses in its own weight.
1 - 5 is basically the story of every single socialist economy in the past 150 years.