Again, my point was about the English character and the seeming contradictions in their celebrations of individuals. I report, you decide. And, to be buried in the floor of a church or cathedral is an honor (eg, have a walk down the aisle in Christ Church, Philadelphia).
And which with time become obliterated due to foot traffic, at Christ Church or anywhere else.
The tombs in floors of those held in esteem are those which are protected from foot traffic -- whether placed in the floor at Westminster, like Churchill or Faraday, or placed in portrait or effigy as with Lister or Newton.
If I can walk on it, I can disrespect it willfully and purposefully. Darwin's slab receives it share of trampling from me and I'm sure from others too.
Consider the fact that there are burials of executed family members of Mary Queen of Scots, and rebel knights at Westminster not buried beneath a trample-able slab in the floor, but in raised boxes and even some with effigies. These individuals are buried with more honor than Darwin or some other one of those folks you mentioned who are squirrled away in a nook somewhere.
Darwin's burial was one attributable to a political favor -- a mere connivance or an expediency at best.
As one who appears to share an interest in the historicity of things as I do, despite the fact that we as scientists have the same scientific facts, but differ in our worldwiews about those facts, for the sake of the accuracy of history, as with science, it pays to know the whole story before one leaps to conclusions.