Greg Wilkins hits the nail squarely on the head:
At Webtide, we sell developer advice, custom development and production support for jetty and dojo cometd. We don't expect our clients to buy our services because of some sort of guilt trip from the value they obtain from those projects. We expect our clients to pay for the value add that we give. The software is free under the terms of the apache 2.0 license and we expect no charity or moral obligation in return.
This pretty much sum's up why most venture-backed Open Source efforts either fail so miserably at building real community or just fail miserably in general. Open Source – to my mind – isn't some talisman you wave over software to instantly take market share from entrenched players or to instantiate your very own +5 Army of Contributors (with the zealotry bonus) for personal gain. Instead, it's a great way to distribute software that should already be a commodity at near the cost of reproduction (roughly bupkis) and prevent network effects from ingraining outsized profits to firms whose marginal utility is suspect. If something is still worth paying for, it's natural to expect that it won't fare well in the world of free software. Too few people are liable to understand its value to create the virtuous cycle of contribution and use that makes the whole thing work. The great news here is that commercial software isn't dead at all. It just has to actually be better.
Open Source (and to similar and complementary extent, open standards) helps drive Pareto-efficient allocation of capital in the software business. That may not be a high calling, but it's a lot easier to justify than living off of monopoly rents for a living, and I take great comfort in knowing that what we do at SitePen adds amazing value (else we wouldn't make a living at it). As with Greg and WebTide, people pay us for what's actually scarce: clue, skill, and hard work.