[ajay_kumar]

Sadly true. I grew up in a socialist country and know from
first hand observation how bad socialism is for creating prosperity.

To expound on your example, a single person earning $10,000 would pay
10,000-2500 personal exemption x 10% = $750.
A family earning $150,000 would pay
150,000-4*2500 x 10% = $14,000.

So 15 people earning $10,000 pay 750 x 15 = $11250

So to me it seems fair.

Obviously a 10% flat tax can not cover all the entitlements.
So the social security system should be optional as a private investment option for the younger generation.

[Myrddin]

Your example assumes a family of 4 gets 4 deductions. I still have 4 people parking knees under my table. One of them is the minimum wage earner. No longer eligible as a deduction. Once that happened, I insisted that he contribute $200/month to cover his groceries. I'm down to 3 deductions now.