I don't think the physical stores lasted long, they eventually were sold off to ComputerLand, possibly as part of a consent decree (before my time). A lot of bad business decisions at IBM start with the various consent decrees it operated under as a result of various antitrust cases, and the utter fear of yet another antitrust case developing.
Yeah it didn't seem like they were really big and would have lasted, but it was kind of a contrast with today where a young person on the street would probably have not idea what IBM does.
IBM was big, really big. At one time, it had more than 70% of the computer business, so it was twice as big as every other computer company added together.
In fact, IBM was really big before computers even arrived. It dominated data processing based on punch cards and was sued for monopoly abuse in the 1930s. It was the original Evil Empire.
Microsoft -- founded in 1975 -- has been spectacularly successful, and IBM's performance has been mediocre for the past 15 years. Even so, Microsoft has only just overtaken IBM in revenues. (Both are now around $93 billion. On any reasonable growth path, IBM would be well over $200 billion.)
Indeed, Microsoft would probably be nowhere without IBM. It was IBM that set the PC standard with the IBM Personal Computer in 1981, and Microsoft was lucky to be part of it. In IBM terms, Microsoft stole a small part of IBM's rightful monopoly. IBM's response was to try to kill it with OS/2 EE and the MCA bus in PS/2 computers, as part of SAA.
I was surprised that IBM even had physical stores at some point and today average consumer probably has absolutely no idea what IBM does.