There are probably multiple reasons for this. I can think of multiple reasons Darwin was more appealing to people. Wallace was religious, and he was not racist (not that Darwin was any worse than most of his time, but Wallace was different).
It was not always so: https://www.bbc.com/news/uk-wales-21549079
There are a number of people who came close to the idea including Erasmus Darwin, Charles Darwin's grandfather.
Wallace failed to promote his role in formulating the theory as effectively as Darwin.
and Darwin was very much on home ground in the UK actively riding on Wallace's extensive field work and spreading a Darwin flavoured spin on the very material Wallace was writing in from the tropics.
Both were very good writers, Darwin had greater visibility during the early days simply by being there to meet, greet, and lecture.
Many of the "Darwin" ideas in the popular mind came from elsewhere; Survival of the fittest was Spencer and although later taken up as a phrse by both Darwin and Wallace it's almost the active opposite of the more passive (and more correct) notion of Survival of the best adapted.
Not sure about that that. Darwin goes on and on and on sometimes - especially about pigeons.
I mean, pigeons
The Formation of Vegetable Mould Through the Action of Worms was a total spade turner.