I agree with you on certain points you have raised and there are arguments to be had on both sides.
I like to line breed my cats, other breeders I am friends with have also line bred their cats and they still have some of the resulting offspring 14-18 years down the line as proof. One of them has been breeding for approx 30 years so they should be qualified enough by now to be able to pass on their opinion on this type of breeding. As I said previously noboby should attempt to breed this way without researching their lines thoroughly first.
I do not sell my cats for breeding regardless of whether they are line bred or outcrossed as I prefer them to go as pets.

I also know of other breeders with a firm belief in outcrossing all the time that have ended up with one or two little 'unexpected surprises' in their litters.

At the end of the day it is up to each breeder to determine the best way forward for their cats.

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