Actually I don't, hence why I came here to ask the question. I think Egol answered it above, they are beatable as small businesses beat them every day. That's what I needed to know, whether they are beatable, how easy/hard is it to beat them as that is a deciding factor as to whether to invest more time and money into SEO or not (money could be better spent on ads for example).
You gave me a philosophical answer that basically said, "you can't change what they do or have so work on what you can change in yourself", which is all fine and dandy but its a loose, vague, cookie cutter spiritual science answer. I mean could I theoretically outrank "British Cancer Research" Website for the keyword cancer "cancer research"? Obviously the answer is yes, using your advice, I can just keep working on my cancer research site, maybe throw a million £ into its SEO and a couple of years and I'll outrank them. We know that, everyone knows that, everyone knows that with hard work and enough time/money/effort you can achieve anything - that is not the question, the question was "how hard/easy is it?" as that is obviously a big factor when considering to continue with that strategy or not.
I mean no disrespect, I think you just misunderstood my question from the start as a "complaining type of question", perhaps you interpreted it as me whinging about the high DA competition and you were trying to encourage me to not focus on that DA. I wasn't complaining, it was a straight up question of how much that high DA is a factor in their site outranking mine as I have built a lot of backlinks to my page, they have none to theirs and therefore must rely on their site DA and traffic.