Given that about 60% of business fail within the first two years (cite) and defining success can be tricky (some business are successful when they fail - tax write off), heck even defining a market is tricky (is it the consumer of your goods or the consumer of your stock), the LAMP stack is just a sidenote.

People, your staff, make or break a business. Now I'm biased and I think the LAMP stack attracts dedicated and talented people. Combining those people with negligible software acquisition costs is not a model for success but it's several less factors for failure. So I think the question you should be asking yourself is why do you think proprietary software means success?