Comment by tacostakohashi

This is true, although different companies manage their vendor exposure with varying levels of effectiveness.

Often, it's ideal to use several / all of the vendors for each thing, and play them off against each other. e.g., have some of your database stuff on oracle, some on mssql, or some cloud stuff on aws and some on azure, make your apps portable, and tell them both that you'll switch to the other unless you get a good deal, with that being a plausible threat because you're already using the other one and know how to make your stuff work on both, and occasionally rotate apps between vendors, or change the mix from 50/50 to 60/40 just to show you can.

Of course, the vendors will be trying to work against this and will want to do some supposedly amazing deal if you go exclusively with them for everything... which might be attractive in the short term, but opens the client up to getting screwed in the long term once they fall into all the lock-in traps and lose the very _ability_ to switch vendors.