Absolutely this would be a governance risk. The reality is that this is not what you see them do. Typically at acquisition they'll throw some bad books of business to runoff, but there is no perpetual moving bad books into runoff from the operating businesses.
Also, they've hit this item hard over time. Look at the disclosure on asbestos in 2015 - the gross liability was $1.38 billion, now it is $794 million. The cost to bring down this exposure has been insane relative to 2015 expectations, but it is coming down overall. Everyone in the space has been surprised that claims just keep coming even as the 1st generation of those exposed to asbestosis are largely passing away. There is a lot of litigation fraud, but there are also a lot of real cases where a parent worked in an asbestos laden facility and were bringing it home and child now has asbestosis.
Outside of asbestos you've also had lifting of statute of limitations on various different crimes that have hurt runoff as well. There are claims on the casualty side in years that you'd have thought would be "closed" in the past because of statute of limitations that are now open again.
In any case, runoff is a real liability and there are likely to be many more years of adverse development here, you just capitalize the current run rate of claims at 10/12/15x and determine for yourself if the rest is still a valuable enough earnings stream.
I also agree with Viking's note above.