The heart is a receipt. It does not carry the post anywhere.
A like on X is still a mark on the original object. Other people’s Following columns do not receive a copy because you bought hearts. The author’s notification stack gets a ping. The public row gets a number. That is the inventory.
People buy this cart hoping the number will “keep the post alive.” Sometimes an early row stops the post looking abandoned in the first hour. It does not purchase a second timeline, and it does not purchase a stay on the profile. Those verbs have their own URLs.