>You can't keep selling infinite ideas.

You cannot sell ideas at all. That is how it should be. Patents cover methods, copyright covers things made. Ideas should always be free.

I do think it is possible to for ideas to be infinite/

>You can't feed infinite amount of sugar to a person.

No, but you can give them all that they want or need. Once that is fulfilled perhaps they might want or need something else.

Maybe someone should research the idea that there might be a heirachy of needs where once one is satisfied, It causes a higher level of desire.

Perhaps it might get quite sophisticated as you go up.