The importance of open source, both in software and hardware, is something that can't be understated. If there is to fair access to technology by anyone who needs it, it's vital that the core of each technology used can be studied and modified by any person that's interested in doing so.
The idea of having any technology locking user to a single vendor because there is no real way around it, is appalling because it means that if something happens to that vendor all investment in time and money will be lost. Not to mention all the information that was in there.
It also means that monopolies are more likely, and if the come to be they will be more easily maintained since there is no option to go to in case of abuse or bad service.
Also, people that need especial adaptations of any software or hardware, could custom make them if that version isn't provided by the original vendor for whatever reason. This can streamline processes, and could bring life saving technologies to the people who need it a lot faster.
By allowing people to get to understand, and work on, the internal workings of whatever technology they are interested in, can have other important by products. With more people working to improve current technology, products that meet particular needs can come to market a lot faster. Also, those improvements needed by a particular group of individuals could make their way a lot faster, since they could get someone to make them with more ease.
Innovations will come faster, since there'll be more people covering a lot more technology. In some cases, it'd mean that there is a bigger chance of people will be working on fields that businesses would not take. Or NGOs could take existing technologies, and adapt them for their needs if they can't get any sponsor to do so.
Having open open source technologies is vital for us. Our society is becoming ever more dependent on technology to live our daily lives, so technology's inner workings have to be available for all of us. More importantly, they have to be easy to access by those who can do something of value with them.
If this doesn't come to happen, we run the risk of having the technology on which we depend on at the hands of a few hands. As history has shown us time and time again, that's not in the best interest of the majority.