Easy. The cost of maintaining a country is based on the GDP
WTF? The cost of maintaining a country is based on the government budget, not GDP. GDP is a measure of economic output. If citizens have good saving habits and the government doesn't run deficits then the cost of maintaining the country can be a small fraction of GDP. For bad savers and runaway spending governments, the cost can be much higher than GDP.
And in your example, trucks are charged a highway tax all their own to help pay their share.
It's sad you work at McD's but stop hating on more economically successfull people. It's clear from your posts that you're a coffee shop marxist.