There are two practical options to replace Concorde in reality. One is a Gulfstream 5 sized biz-jet such as
Aerion. The other would need to be about 777 capacity with trans-Pacific range to begin to make the economics viable. We may see the first one relatively soon if they find suitable investment. Don't hold your breath for the second one.
I doubt a waverider will be viable for that although I should think the military will find a use for it.