Reason 1: It's one of the most basic freedoms you have. Nobody can force you to play something on the guitar, as you can practice what you like. By giving it up it almost like returning to your cell after walking outside; you just won't feel the same without it.
Reason 2: Other more popular bands/musicians in the industry have got where they are by sticking at what they do. A lot of them have done so in defiance of what people have said about them, including those who review them. Don't ever believe that you are crap just because some guy with a fancy degree in music/english says you sound bad. Maybe you might need a bit of work, but journalists are paid to be biased, as biased articles sell more then impartial ones.
Reason 3: If you find that you can't find musicians who are interested in joining a band immediately near you, search websites like Joinmyband and this one to advertise yourself to people who will be interested in what you are doing. It's simply a case of asking the right people.
Reason 4: Playing your instrument is fun. So what if you don't have a band immediately or have thousands in equipment, are you really going to let that destroy your hobby? It's something that you can do without having to answer to anybody when you get home. You can play songs the way you want them, simply playing to relax is very therapeutic. Don't whatever you do simply put your instrument(s) on ebay because you can't play it straight away. You have to practice at anything worthwhile to become good at it.