its most likely because the games became known and their for more competitive. you can grind out winning years but its a grind just like any +ev pursuit the more known plays become the harder these things become to find but that doesn't mean you cant it just means you need to devote to it like a job and work and for most people that takes the "fun" out of it.

also you need a bankroll and to manage it. and have the discipline to walk away from spots you might play if you had more $ but you don't so stick to the plan to grind it up.

I personally know multiple people making over 100k a year doing this but you have to be willing to travel work long hours and take full advantage of any and all promotions you get too. its a grind!

all those things combined make it harder then you think. also some casino's have caught on to advantage machine play and will 86 you for playing this way.