It's happening faster than you think... the StarWorld had two roulette tables in late November, and had just installed the electronic terminals in a different location.
In December - the two tables were gone in favor of the electronic terminals.
StarWorld is the largest of the local operations and attracts a pretty big crowd. Well ok, perhaps the deformed pineapple... er... Grand Lisboa... has more. But maybe StarWorld is just being innovative - they were also the only casino that I know of that installed the Pokertek tables.
Last month - at the Venetian, there are a number of roulette tables, but not overly busy. They don't have any with electronic terminals, but they have the standalone automated roulette wheels as well, and they weren't doing that well either.
Slots are picking up. Still slow, but more and more locals are starting to try the slots. The worst thing, however, is that many people still play one line
Drives me batty... in most casinos they are stuck in the worst locations and as you pointed out, take very little of the total space. In the Venetian, however, the slots take up a lot more space, but I think tables still occupy roughly 80% of the space.
Nevertheless, as long as the slots are set as tight as they are in Macau, they will never be a major source of income. I could walk into the worst/tightest ripoff joint on the Strip (the Aladdin/Planet Hollywood) and still do way better than any casino in Macau.