What you're left with are development, support, and leadership. If any money is coming in, it's coming in for support. Even if you're not doing all the development yourself, you must still organize and direct it. Then there's leadership, which can be as simple as a boss and a secretary to keep the lights on.
Trouble is, unless you can find an additional business model (hardware, SaaS) there is never any additional money to pay for things traditional companies take for granted.
Advertising -- I've been doing this blog for nearly five years and chances are good there's still a Microsoft ad next to it. (I just checked and goody-goody there's Novell.) Sometimes there's an IBM ad. (There is today.) But the open source corporate bench is now wide and deep. Where is my Alfresco ad? Matt is dead right on this.
Tschotskes -- Yiddish for "little gift." (Yiddish is the second language of the New York diaspora.) Marc Fleury once gave me a JBOSS t-shirt riffing on the movie "Napoleon Dynamite." But generally the cupboards are bare. Quite a contrast to the PC beat or the Internet beat, or even the medical beat where inscribed pens, shirts, gimcracks and gewgaws are de rigeur.
Travel -- Does Linus Torvalds even have a frequent flyer account? A few luminaries like Stallman, Perens, and Shuttleworth go to exotic locales (or come from them) but the average open source exec-on-the-street knows mainly the Portland coffee shops and perhaps the train schedule to San Jose.
Bonuses -- I don't think these have disappeared entirely. If you can get a hospital or Fortunate 500 outfit to sign their name on the line that is dotted on a support or services contract, you deserve a bonus. But this does not happen often.
Marketing -- Most of the marketing I see coming out of open source is public relations, and sorry to say it is little changed from when I started in journalism 30 years ago. Everything is still pitched from the client's point of view, not the writer's and not the publication's. I think this budget can be squeezed further. Maybe send us some tschotskes instead.
Fancy Dinners -- No, taking the development team out for eggs after they have pulled another all-nighter does not count. Fancy Feast does not count, either. Open source had traded in their Starbucks cups for McCafe long before that became fashionable. I know they eat well at the Googleplex, but they're an online outfit, not an open source company.
Strategery -- I know, it's spelled strategy. But if Forrester or the other old-line market research outfits depended on open source the Forrester walk would be to the end of a plank (followed by the sound of a splash). Research? What do you think beta code is for?
These are just a few of the functions I grew accustomed to over 20 years covering technology that I have seen very little of since joining the open source beat almost five years ago.