They might have caught the mistakes but I think the resulting product would have been a flop.

If IBM hadn't done what it did somebody else would have dominated the market with a product to fit the same niche. Perhaps somebody "downmarket" in the more consumer space who managed to punch upwards -- maybe Apple who had some business success with the Apple II + VisiCalc, etc. or maybe Kaypro or somebody in the CP/M space. Or perhaps somebody else "upmarket" like DEC, who came too late the personal computer space with products that nobody really bought (DEC Rainbow, etc) but maybe they'd have had more success if IBM hadn't gotten in there.

The market wanted a relatively open product to innovate in. When the PS/2 came along a few years later with proprietary bus, etc and tried to put the genie back in the bottle, it flopped.