Larger companies have no problems finding people to pay to support Linux, or if they are really large (say, Amazon), supporting it themselves and being who people (including big companies) pay to support and host Linux systems.
it all depends on size. some larger (typically older) companies with smaller engineering teams will make the tradeoff you are describing. But the big players today, who manage hundreds of thousands to millions of servers are not going to pay per machine / per core license counts for support. They build and maintain most of their own software for their own needs.
If it's going to run Linux, you tick that option when ordering. Or you tick "no OS".