In my experience my neighbours inheritance planning is to leave it all to the Son and the girls have to fend for themselves. Causes family problems big time, and unfair as hell.
I do not know of any son that has had to buy out his siblings. The exception is when no family member wishes to farm then a sale is then divided on death of the parents.
I do, next door neighbour. His father died unexpectedly, and the son had to sell a farm and other property to pay out his sisters. Luckily for him, they had the money and property to do it in the first place.
For the farming son (or daughter in one case) the land is a means of making a living. For the other siblings it is an awful lot of money so why should he get it all.