Love is the default state of humans. It's always real when it exists. Love is a measure of how willing people are to cooperate and inclination to prosocial behavior.

Transference love is always real love, it just is not enduring love in the case when T is putting aside priorities that would otherwise make it harder for both client and T to cooperate in life.

This stuff about parents and "old stuff" is not true. It's all very silly. Love is who we are meant to be. Babies & children love because they have no expectations and no obligations to fulfill, they do not have to worry about survival.

So, love and work are two opposing forces. Typically the T:client relationship is an exchange of work for love, that's why the love can be so intense, no work is required from the client. It would usually be hard to love T quite as much after the relationship because there will be a more equal balance of work and love. But that doesn't mean you can't enduringly love T, just that therapy temporary is simulating a lack of work.