SPY - Asset Value

From Q1 of 2017 to present, the US federal debt has increased from $20T to $34T. Assuming the average US assets have increased in value at the same rate as US federal debt, then SPY should be valued at $340 (at 2017, SPY was around $200). However, the current SPY is valued at $485,  which is 42.6% higher than $340, why?

A simple explanation -- the stock market is seriously overvalued, Wall Street is intentionally inflating the bubble.