Microsoft was, and still is, a giant tech company starting in the 90's and on. But if one looks at the digital corporate landscape back in the 1980s, IBM was an absolute behemoth. Consider this. In 1985, IBM had a market cap of $95 billion. That was more than the next 13 largest tech companies at the time, combined! This other group includes Apple, HP, Hitachi, Intel, Motorola, Sony, AT&T, Texas Instruments, Verizon, Xerox, National Semiconductor, DEC, and Control Data.
It's hard to overstate how powerful IBM was at its zenith.
I only know this because I was curious and looked up the data the other day, and it blew me away.