And for the more recent autosomnal tests that claim to link people connected since abt. 1800 the business model of the test only really works for people that can't trace their ancestors on paper to 1800 (who are often Americans and adoptees). i.e. someone pays for the test and in return they are told who they match in the testing company's database so that they can work out how their papertrails link up.
In the case of many Brits who can already trace their ancestors back to 1800 on paper taking this sort of test is a waste of money as they will not find out anything more than they already know. Why should they give both money and the information they already have (their papertrail and DNA) to someone else? The economics just don't make any sense. If testing companies want this information they should be paying us Brits for it.
Well, I can trace my paternal ancestors back to 1800, and I've taken
autosomal and Y-DNA tests. Why would I want to do that ? Because, when you go back beyond 1841, it is very difficult to establish family relationships. My g.g. grandfather was born abt 1805, and he lived in (what is now) part of SE London, but what was then a small town in Kent. The earliest I can place him in the area is in 1833, when he got married, but the town has about 8 or 9 families with the same name who share both the same surname and the same occupation. These families all seemed very close, but I can't work out whether they were close because of family ties, or if they all shared the same profession. I'm also fairly sure that the families didn't originate from the town, and I think they originally came from Middlesex, and Middlesex covered just about the whole of the northern part of what we now call Greater London. Hopefully, DNA tests might throw some light on where they originally came from. This information may not be instantly available, but might come to light as more people in the UK take the tests.
Why should they give both money and the information they already have (their papertrail and DNA) to someone else?
Well, to me, genealogy is all about sharing information with others. Without the tireless (and often unpaid) work of people who indexed and digitised the censuses and BMD registers, let's face it, not many of us would have got very far. It's all very well and good to sit in front of a PC and gain access to 1000's of ancestral records, and then pat yourself on the back and tell yourself what a clever person you've been, when really the only value you've put in is to pay a couple of hundred quid to one or two genealogy web sites, and some BMD certificates which you found via those sites. Whilst it would be wonderful to be able to do the same thing with a DNA database, with everyone getting tested free, with cheap access, the reality is that DNA testing is time-consuming to perform, and therefore quite expensive, so it's not going to happen, but it is getting steadlily cheaper. A DNA test is never going to completely unravel anyone's family tree, and it would be foolish to assume otherwise, but it is another useful tool.