>>126555951personally I put the blame on Lisa being the only regular character her VA voices on the show*, so Lisa ALWAYS has to have voice lines and plot relevance in some manner because she gets paid the same as the other main cast VA's even though they contribute so much more to the show overall so they have to include Lisa a bunch to justify that expense
*meanwhile Dan Castanella voices a bunch of characters besides Homer, Julie Kavner does Patty & Selma as well as Marge, Nancy Cartwright does a bunch of other kid characters on the show besides Bart, and of course Hank Azaria and Harry Shearer both voice most of the recurring adult male characters not done by Dan Castanella, so Yeardley Smith only doing Lisa on a regular basis is just bizarre in comparison