And indeed one of Marx key predictions was that capitalism through increasing efficiency would eventually lead to an overproduction/under-employment crisis.
You don't get to keep waiting for a prediction to finally come true when it doesn't come with a deadline. It already didn't happen despite all our labor saving technology so far (we don't even weave cloth by hand anymore!). Sure it might happen in another 100 years, or another 1000. But that's almost a given for most predictions.