If you don't delegate, then you cannot handle thousands of cases and you should not try. I'm not sure that criticizing those who do delegate is meaningful.
I don't recall making such criticisms, beyond making the commonsense observation that overloading one's docket risks diluting one's energies to the point of dereliction of duty. I don't believe this idea of "spreading oneself to thin" is unique to patent work, but is universal to any kind of work. If one is delegating, one isn't handling thousands of cases, but instead, performing an administrative/logistical function, and placing one's trust in one's colleagues or lieutenants.
Handling 100 active dockets means a response will come due on average once every few days. Handling 1,000 dockets means a response will come due perhaps on average once a day, and there will be many days with more than one response due. If even a third of those are non-final or final rejections that have to be substantively responded to and thus require reference review, critical contemplation, discussion or (worse) evidence gathering, no single person could reasonably handle such a workload with the diligence and professional care that a client deserves. ("Delegating" isn't using diligence and professional care if one is signing off on others' work without putting in needed critical review beforehand, which can often take just as much time as what has already been put into the work.)
As for the inherent superiority of in-house counsel over outside counsel, outside counsel can't afford to spend
decades understanding the client's technology and the market, and therefore can neither write specifications of surpassing quality technically nor prosecute claims that provide maximal commercial value for the client. Pointing this out is not puffery but purely an issue of cost-benefit: outside counsel isn't interested in, and can't afford to be interested in, the company's business, they're interested in lawyering and charging billable hours. In-house counsel can afford to be much more intimately involved in engineering, product development, marketing, sales, regulatory aspects, etc., etc. Asking for such broad and deep expertise within one company's area is too much to ask of someone who works in a firm--they've got other things they need to be doing, since a firm attorney's overriding duty is to his firm. This oughtn't be a controversial opinion: firm lawyers, first and foremost, want to keep their jobs.
As for us, when we need outside counsel, we use it--but generally only for things we can't do ourselves, for lack of license, credential, or experience, such as foreign prosecution.
Klav's understanding of my broader meaning of "client" as I've used it here is correct, as, I think, is his deeper analysis with respect to how serving a "corporation as a whole" involves mindfulness and gentle attention to interacting and often competing internal interests.
I'm a bit surprised this philosophy appears to be meeting resistance here. It seems self-evident to me, but perhaps not everyone has been treated to the in-house experience. (Isaac?)