Why does Betty Tanager tell her husband she doesn't want to wait for tenure?

I feel that the Tenure Conundrum can't be untangled in just one sentence. We must first delve deeper into these 2 fictional characters. Consider their relationship, for example: They're eager to answer each other's needs at the drop of a hat, as if they're 2 parts of the same whole, but are perhaps unable to listen to those around them and assist them. Why would one of these 2 fictional characters - or even both - desire a permanent position in a communal organization that thrives on shared knowledge and solidarity? Wouldn't their discriminating idiosyncrasies be ultimately appreciated elsewhere?

She says she doesn't care about tenure, she just wants to start a family, and she is concerned that if she keeps waiting she might not be able to conceive.