Except that, over the same time period, IBM was also very successful at innovation and investing in technologies. Yes, they made some very high-profile misses that the top poster lists, but they were still a powerhouse doing other stuff during that time (as a commenter replying to that points out).

Except all the technologies listed were basically in the heydey of the 70s and 80s. Gerstner redirected IBM into an enterprise services business in the early 90s and by the late 90s that's where all their money was. The 2002 acquisition of PwC consulting cemented this shift. In the mid 2010s under Ginni Rometty IBM software became secondary and it abandoned selling it as standalone software instead bundling it into its consultancy.

So IBM hasn't been doing hardware R&D for about three decades and abandoned software R&D well over a decade ago. R&D hasn't been in their DNA for a long time, their previous contributions notwithstanding.