There are huge difference between tax and transaction fees, such as :
1. Transaction fees is created to prevent network spam, while tax is created to sustain government and it's project
2. Transaction fees rate depends on it's TPS and network TPS capacity, while tax rate depends on law.
3. Transaction fees is extra reward for miner, while tax is required if you want to see your country grow.
If bitcoin or blockchain-based cryptocurrency don't have transaction fees, surely we'll see people spam transaction which leads to bloating blockchain size, higher network/nodes loads and could lead to centralization.
Wrong. No one actually buys things with BTC so it doesn't matter. Your spam is someone else trying to buy a coffee with BTC. With hight fees TC is a $100 note. Just for the rich.
No fees, no miners the same way no tax, no hospitals.