That's the grade school analysis and in reality we are all poorer for it.
If ten people pay $5k to avoid getting a substandard service that has a 1/10 chance of happening and will cost $20k to remediate if it does that is a massive loss to the overall economy because that money otherwise would've been spent elsewhere else.
This isn't just septics, it's every widget and service. And it's not just a government and tax problem (though those cases are frequently most flagrant). Private industry requirements cause the same problems.