This!! Couldn’t agree more. While I do think the physical card system could be improved (and ideally moved online), the biggest bottleneck is almost always baggage arrival. We were recently back from overseas and, despite clearing immigration with hundreds of people lining up for the green/yellow card (around a 30-minute wait), we got to the carousel to find not a single bag out yet. Ended up waiting close to 45mins before all luggage arrived and we could finally exit.
In contrast, on our trip through Singapore, we cleared immigration in about 15–20 minutes. By the time we reached the baggage carousel, unloading had already finished and our bags were neatly placed to the side with others, presumably cleared to make room for the next flight.