note that the common problem in both cases is in ignoring a large portion of your users use cases, forcing those users to use different things in different places.
RedHat got it's foot in the datacenter door BECAUSE it was the most popular desktop linux at the time. Admins installed it in the datacenter because they were familiar with using it outside the datacenter.
Microsoft also took over many datacenters because it (superficially anyway) was the same as the desktops that people were running.
Ignoring either side of things opens the door for someone else to edge you out.