> ventures that others didn't see any opportunity in
Others have always seen opportunity in the two things that actually work from Musk's empire[1]:
Tesla was a going concern before Musk - and electric cars were well on the map from other manufacturers, as shown by the fact that electric cars have been around since the dawn of motor vehicles. Although advances in related tech, including, IT, were important in moving from the mere daily use of electric vehicles in the 1930s on to meeting the speed requirements of the travelling salesman: the desire and eye to the opportunity were always there - held back mainly because of the lobbying by the internal combustion guys.
Reusable rocketry - it wasn't moving as fast as we'd've liked, with things like the cancellation of the DC-X Delta Clipper. Although advances in related tech, including IT, were important in allowing engineers to move on from a test item to fully working vehicles. As even the Wikipedia the timeline shows, there has been a pretty much continual interest in private companies in space operations, including launch.
> But he's also been proved wrong on several occasions.
That gives us two (count them, two[1, again]) times he has continued - admittedly, with a certain "flair" - to get other people to fund things that were ripe opportunities that the relevant private industries were already well aware of. Now, those have grown in size and popular exposure, but the count is still two.
Now, how about things where, in fact, (except a certain breed of, what is the word - charlatans) "others didn't see any opportunity": hyperloop, boring holes for even more roads, solar panel shingles, flame throwers amongst them. Plus the "opportunities" that he "spotted" for his actually functional companies to work on: Cybertruck, the battery-powered big rig (what am I forgetting here?).
We all expect things like VC funding to have hits and misses - and if Musk restricted himself to claiming to be a VC we'd probably cut him some more slack. But so far the rate of spotting successful opportunities that others missed - and making them work - seems to be very close to zero. Getting funding for opportunities that others were all too aware off and speeding them up, okay, granted.
> more accurately, his engineers have achieved
Very true.
[1] No, not counting PayPal, for obvious reasons.