It's hard to tell if this is a serious question or not, but here goes.
There are some "universal" trees online, like wikitree and others, but they are only as good as the information in them. Some of this information is good, some is the usual rubbish such as children born when their parents are 8 or 108.
As to why all the census, parish, probate, tax, legal, etc records aren't readily available. There are many millions of records in Britain, billions if one includes all of Europe and all English speaking countries. Transcribing, indexing and putting this information online requires an immense amount of work, millions of hours of it, some of it done by volunteers, some of it done by companies who charge for it.
Why hasn't this all been done? (Stamps foot impatiently.)