When I started going online back in 1994 the world was quite small. There were some local BBS around, I had my analogue modem with fast 14.400 bit/s, that needed to run over my phone line, and that was it. There've been services around, which were like bigger BBSes, like Compuserve or AOL, which ruled most of the market.
Then out of nowhere the Internet emerged. Compuserve, AOL and others were proprietary systems only, and the established companies needed to decide what to do. Well, they even didn't notive the Internet and its potential first. Open standards, decentralized, not ruled by only one entity. This was something new and it wrecked their business models great lenghts. When the Internet started to became more and more important, the content of proprietary standards in AOL and Compuserve became less and less important and newsworthy since all this content drained into the Internet.
So what's the lesson of it? A proprietary system is like an island. It might be nice for a while, but when something better becomes available, most of its content will shift definitely there, ruining your old business modell, forcing you to adapt. That's why in my opinion Linden Lab is working at an open standard at the moment, because they don't want to be the next Netscape. They still want to be in business in the next five years and this is definitely a way to achieve it.