If someone buys an expensive piece of proprietary software management and lawyers will spend ages poring over the contract/license which will be specific to that piece of software, especially if it's going to be sold on as part of a product. So why is it so difficult to read the license on open-source software?

There's a very easy way to comply with Open Source licence requirements. Just release your Source Code!

Just as you built on top of other people's hard work, other people deserve to benefit from your hard work.