That's really part of the problem of doing a bootstrapped or early angel type startup, and I definitely feel this guys pain. You spend years doing very shallow

That's really part of the problem of doing a bootstrapped or early angel type startup, and I definitely feel this guys pain. You spend years doing very shallow work because you simply do not have the time or money to dig deep into any given issue until it actually crops up, at which point you do the bare minimum to fix it and move on. Repeat this process until you fail to find a viable business model, or find a viable business model at which point if you're really lucky you can start slowly rewriting your app piece by piece, but more realistically you just accept that it was good enough and keep doing more new things. This skillset just isn't that useful to a large software shop.