I guess we'll never know. However, my feeling is that Jeremy was adopted for the sole purpose of making him heir to the farm. I don't mean that to sound callous, but I don't believe that any thought was given to what either child might wish to do with their lives.
I would guess that most people had little or no understanding of the sensitivities of adoption.
Back in the late 50s, early 60's the attitude to adoption was so different compared to today. Also many adopters were pretty ignorant about the sensitivities of a child whom they had adopted. Some would naturally realise their child was vulnerable and needed special love and understanding but mamy were just expected to fit in and toe the line.
Why would a child adopted by such a wealthy family not be forever grateful to the parents who adopted him/her? Why would they not happily take over the family business whatever that may have been. There are natural children who cannot and will not work in the family business as they feel no empathy toward it, therefore surely it's no surprise that an adopted child may not feel the excitement of working the land if there was no genetic connection to it.
