Civil forfeiture was a highly successful tool to combat organized crime and grew enormously in the 80s with Reagan's odious war on drugs. It basically solves the problem of illicitly used money being able to free people the government wanted wanted to stop.
As a tool for dismantling organized crime, it was effective, useful, and generally seemed basically fair and as such seemed to survive court review.
Then came the war on drugs and a dose of right-wing anti-tax thinking.
"It's now possible for a drug dealer to serve time in a forfeiture-financed prison after being arrested by agents driving a forfeiture-provided automobile while working in a forfeiture-funded sting operation." — Reagan attorney general Richard Thornburgh in 1989.
It was specifically designed to help fund agencies in a way that replaced tax revenue. Starting at roughly this same time period most government agencies at all levels became cash-strapped in various ways. This meant some agencies have turned to civil forfeiture to create revenue.
It's clearly a bad incentive and needs to be reined in and reformulated to ensure rights are being respected.
BTW, a heavily armed citizenry is precisely why local police departments advocate for more and more militarized equipment. They'll call them gang members and drug dealers, but they are heavily armed citizenry nonetheless. Armed citizens won't solve any part of this problem.