I don't think ebikes are replacing walking trips though, but car trips. The requirement to anticipate, prepare for, and endure the weather (including cold, snow, rain) makes bikes much less appealing to people who already own cars, which is almost everyone in the US.
I think the main reasons bikes aren't popular are:
safety (perceived)
weather
cargo capacity
effort requirement
Enthusiasts don't mind the latter and reluctant cyclists will still find sufficient deterrents even if it's eliminated. So I don't think ebikes are really going to move the needle in terms of ridership, regardless of what their buyers tell themselves at time of purchase.
I think the main reasons bikes aren't popular are: safety (perceived) weather cargo capacity effort requirement
Enthusiasts don't mind the latter and reluctant cyclists will still find sufficient deterrents even if it's eliminated. So I don't think ebikes are really going to move the needle in terms of ridership, regardless of what their buyers tell themselves at time of purchase.