What explains HUGE difference Between House Edge verses Hold % on casino games?

Bob is wrong. If you make $1000 in bets, you've still wagered $1000 regardless of your initial bankroll. The reason for the discrepancy is the fault of bad gambling habits. For example, many players will martingale, causing large losses, others won't quit while they are ahead, so they never have a take home amount equal to their wins, and finally there are those with just bad playing strategy. If you play bad blackjack strategy, it can increase the house edge tremendously.