Like all the big corporations IBM has bought a lot of small competitors in the past. Red Hat was the only name widely known to the public because IBM targets are software tools for business or the backend of the enterprise infrastructure.
Here there is a list of all their acquisitions.
Meanwhile from the beginning of the years 2000s they decided they wanted to become a consultancy company and rely more on external developers (especially from Indian companies). Internal developers slowly became demoralised in the middle of repeated rounds of redundancies, the quality of their services declined and they lost a lot of clients.
You may see IBM as an innovative company, a little bit for their past reputation and a little bit for the recent advanced projects they announced. But although they have some very advanced research centers the bulk of their work is the one they carry out on the client sites. That part of their work is lagging behind. At the end of the '90s you could find many big companies around the world that handed over to IBM almost all their IT systems. Now it does not happen any more. They are one of the many providers.
Did you notice how the quality of the results returned by google degraded over the years? When it started they had to take out of the market the competition and they strived to return the best possible results. When they became an oligopoly with their alter ego bing they begun to restrict the navigation to the sites in their friendly network.
The other big sites played the same game sharing links mostly with the other big known sites, the media took part in the game by attracting the attention on those big known sites. A combination of restricted horizon, but with overload of information to reduce the users need to look outside that horizon. This is the result you see today.