Read and try to understand the words. They had a growing tax burden because they didn't pay their taxes, not because of Brexit. The business never made a profit. He had to make excuses for why his business failed. What would you expect him to say? Maybe something like, "We chose the wrong type of product to make", " We didn't realise that it's so hard to make a profit when you make a niche product" or " We managed the few resources we had badly". I can't ever remember a failed business owner actually saying anything like that. Instead, it's the economic climate, the bankers, the government, the customers or anything else but themselves and their ideas.
If you knew anything about manufacturing, you'd know that it takes massive investment to launch a new brand of something like a motorcycle. Norton was always little more than a few enthusiasts working in a shed on a shoestring, hoping that a large investor would come along one day and make their dream come true. That didn't happen, though there's still a glimmer of hope for the project.
You're suffering from BDS. You're completely unbalanced. Look back at your posts in this thread. Every post you make is negative. Not one negative prediction that you've made has come true. You spend all your time searching for things to get enranged about. That's not healthy!