'Tis what you're used to
It's more a question of money. Ball returns cost more. Everybody wants to cut costs and don't want to pay more for ball returns. To me, problems with returns are acceptable for the ease and speed of reracking the balls. Golf really makes no difference to me but I disagree on the One Pocket. Having to pull balls out of a pocket breaks my rhythm. For some reason, I've seen fewer tables with ball returns in the South than I ever did in NYS. I've seen way more places that cut way more corners than any place I played in the NE.
Pushout, thanks for the follow-up reply and your viewpoints. I guess this is a question of perception. You nailed it on the head when you mentioned about way less ball-return-system-based tables in the South vs. the North. I'm a native NY'er that spent 8 years in the U.S. Navy, stationed aboard ships home-ported in the South (e.g. Norfolk, VA), so I know what you're talking about and can personally attest to it.
As for having to break one's rhythm by pulling balls out of a pocket in games like One Pocket and Straight Pool, I'd grown accustomed to it by spending oodles of time on drop-pocket-based tables, I don't even think about it -- while still looking at the table/shot, I just walk over and pull the balls out, and then go back to the shot. For me, it actually FORCES me to look at the table/pattern from a different angle. Very often, I make slight changes in my pattern or shot selection based on something I "saw" from the different angle while pulling balls out of the pocket, that I would not have seen if I'd just stayed in position for the next shot that I'd originally had in mind just prior to pocketing that last ball. Just goes to show it's a perception / what-you're-used-to thing. I *do* like the One Pocket option for the Diamond tables, though, where there's two separate cubbyholes in the ball return tray, corresponding to the two target pockets in One Pocket.
Anyway, back on topic with this thread, folks who've become used to drop-pocket tables (in locations that chose to cut costs by choosing drop-pocket tables to begin with, as you pointed out) are generally in the habit of emptying pockets, because they'd been burned with the "shooter's pocket-emptying responsibility" clause in the rules. What's really funny to watch is someone like myself, who, while walking around to the next shot on a ball-return-based table, will habitually (without looking down) put his hand in the pockets to empty any balls, only to suddenly realize when his fingers encounter the steel rebar raceway, "hey numskull, this is a ball-return-table!"

My opponent and I both get a laugh -- myself for looking up at my opponent's crinkled eyebrows, "what in the world are you doing?" facial expression, and then my opponent after he/she sees my embarrassment when I realize it's a ball-return-based table.
-Sean