When a friend has had all the help he needs for building an Upstairs to his house, there is no more from that. Same for the Backyard and Cellar and Friend zones/gates. There is only a finite small number of things to get Friend Tokens for from each friend.
And they might actually be getting help from others of their friends, the first person every 20 or whatever hours to help them out wins the tokens.

I have not had any Friend Tokens from anybody for 300+ days other than from one friend who recently rejoined the game.

The only Friend Tokens I now get are from my Giants Quest and Wealth Quest and from any Statue Fragment I give away.

Hey Susan, I go see Sasha periodically and click on the I want to remove a buddy tab, then anyone who hasn't played in the last 30 days or so, gets the axe, unless I see they haven't posted at all on their regular profile. If there are no posts,then I figure they have computer issues, so I give them 60 days. I try to replace these friends with newer players, that way I can help them and get my tokens, lol.