This demand is handled quite nicely by BA. Last time I looked, Glasgow, Newcastle and Manchester were all served by BA operating to London Heathrow T5, from where you can connect on BA to pretty much every mainstream destination in Europe and the world, with no more changes than you need to do with Emirates (unless you are physically travelling to Dubai itself). In fact the BA service from each of these regional airports to Heathrow is the highest frequency service out of these airports.
Unless of course your connection involves a bus transfer from T5 to T3, which it will do for some connections or Oneworld/codeshare flights. BA cannot offer 1-stop services from the regions to Australia either, which is quite a significant market. Not that they ever could, but it's a plus point for the Gulf-based airlines.
I am not saying BA are not offering the services, just that the Gulf airlines have taken a large bite out of the regional market compared to when they were smaller players.
Emirates has made a niche in selling to people who buy only on price (and presumably are thin as well so they don't notice the 10-across seating squashed into their 777s, or don't notice the hell-hole that is Dubai connections in the middle of the night, with half of Africa and Asia sleeping on the terminal floor all around you). There will always be those who go shopping at Asda just for price, that doesn't mean that Waitrose, M&S, Morrisons etc have no role in the shopping world.
Of course, there are a lot of price sensitive consumers in today's market. However, if you think that Etihad, Emirates and Qatar fill their frequencies from Manchester with passengers solely in this category, you would be wrong. I am not going to debate about which airlines offer the better product, because everyone has their preferences, but I don't think BA is all that special. For many, it's about convenience as well.