As a solo practitioner, I'd like to explain the advantages of going the other way.
Yes you will pay more to work with a big firm, but there can be added-value that makes it worth it. The software consultant working through a large organization may not get specific support from that large organization that provides a benefit to you, the client. In the case of a large law firm that specializes in IP, the individual working on your case can get advice from their colleagues who might have specialist knowledge. They also have sophisticated docketing systems, and back ups to those systems, to make sure an important deadline is not missed.
Also, anyone can have a blind spot. A solo practitioner can get set in their ways and blind spots can develop and persist.
Some caveats: there is a big difference between a 100 attorney IP firm and a 100 attorney general law firm with five IP attorneys. Also, if you have a complex case and can get the attention of a top patent attorney, and can afford him/her, that might be the way to go. But, if you get won over by a "name" partner who then hands you off to someone very jr, that is another matter.