I have a 2008 Mazda 3i Touring (2.0L engine) with a manual transmission, ~130k miles on it. For a few weeks, whenever I shifted gears the engine would rev (up to 3000-4000 rpm) for a second or two before the gear "engaged" and produced power as usual - almost as if the clutch was still in a bit even though it wasn't. This happened in all gears, but was more noticeable in the lower gears (especially getting going in first and shifting to second). I recall it happened both while upshifting and downshifting, but I'm not 100% on that.
Tonight, while my wife was driving the car, she called and said the car stopped putting power to the wheels entirely and the car coasted to a stop. The engine was still running, and she could rev it while in neutral, but it wouldn't go. We're having it towed to the house to diagnose it more in the morning.
I've taken reasonably good care of the car, though it's only been driven about 1 day a week for the last 6 months (total distances each time of ~15 miles or less).
What are the likely reasons for this and how difficult is a repair?