It's not a safe bet. I've build project under AGPL, and made plenty of money doing it. There are places where open is good business, and there are places where proprietary is good business, and there's everything in between. AGPL was nice since I could be open, which had huge market advantage, but release code which my competitors would /never/ take advantage of. It had, quite literally, zero downsides, and a lot of upsides.

There are projects where I do 100% proprietary too, and a mix. It's a business decision. It's not as stupid as proprietary=profit and open=charity. It's a business calculation in every case.