Go on print infinite money and see where that gets you. Governments have to have sensible monetary policy if it is to be worth anything in the long run so yes "there is only so much money to go around". No with matter replicators you wouldn't have infinite material wealth unless you also had infinite energy. If you have both of those then a lot of our problems are pretty much solved. Well probably not because we'd find a way to **** it up.
Sorry I just don't buy that argument. For one it simply isn't true, it doesn't damage society and it can make it better. The US had tax rates between 70% and 90% for the highest earners from the start of WW2 up until 1980 and during that time it was the the engine of the world economy and had a huge increase in standard of living across society. Secondly the problem with your argument is there always has to be people at the bottom of the pile who are forgotten and left to live hand to mouth, pay cheque to pay cheque and remove one pay cheque and they are in real crisis of not being able to pay their mortgage, rent and buy food or other essentials. Society is always going to need people to empty bins, sweep streets, clean sewers, clean offices and hospitals, drive buses, work in restaurants, the list of jobs where pay is terrible but we have to have them goes on and on. So for these people you just say "you should have worked harder in school" or words to that effect. Thing is if they had all worked harder in school or go back to school later in life who does those jobs? Unless of course you want to pay all those people a wage that not only allows them a good standard of living but also to save a little each month for a rainy day or tax them at a lower rate that achieves the same thing?
Taxation isn't fair in the way you want it to be. Everyone paying 20% might seem fair but it isn't. What someone can do with that extra £200 a month when paying a lower tax rate as they have a low income compared 20k or 200k a month is obvious. Someone with 5 million more a year will have bought a house that costs probably 1 million + and will take expensive holidays and buy a more expensive car. If you take an extra 10% in tax of what they earn after the first million they still buy a house, they still buy a car and they still go on holiday, they will still be motivated to work and try and earn more.
Who is demonising rich people? Where has anyone said that? I have no problem with people earning lots of money. Good luck to them, I just think they can pay more in tax than those at the other end of the spectrum as a percentage of what they earn. Giving tax cuts to the mega rich and paying for it by adding it to the national debt is stupid, especially in good times.
You do love to thrown around insults at anyone that doesn't agree with your world view don't you.