I'm not denying all of Cord-Hislop Aerospace, I'm denying some of the information you've claimed (without evidence).
Show me the evidence, the proof where Cord-Hislop is specifically able to produce their own fleet (or called the largest shipwrights in the alliance).
So, I actually just dug out my electronic copy of Ascension to search the transcript and refresh my memory on the matter. Cord-Hislop is actually described as a "midsized starship manufacturer" - as in, midsized for the galaxy at large, not just for the Alliance- which is an impressive status for a human company as it is. If you haven't read the books, I recommend you do. They add a fair amount of back story and extra information to the lore. I get the impression that you just Googled and looked up Cord-Hislop on the mass effect wiki.
Whether or not they are the largest starship manufacturer in the Alliance itself is not mentioned, my mistake if that is not correct (however, I'm pretty solid on Mass Effect lore so I would be surprised if I can't find the reference. It is, however, not in Ascension or Retribution). The book also goes into detail about the massive wealth of this company, and that they are a well-known starship manufacturer in the galaxy.
Regardless, a starship manufacturer that is large enough to coerce a government to construct a top-secret aerospace project in a joint effort with an alien government whom they were previously at war with - and consequently have full access to blueprints such that they could reconstruct a second version of that ship...is obviously an extremely powerful corporation.
So to ignore that Cerberus is behind a starship manufacturer with those capabilities, and then wonder how they could have possibly obtained a sizeable fleet over a span of thirty years is again, pretty dense in my opinion. It's sort of like burying one's head in the sand and ignoring the evidence.
It's not like TIM is running a Ma and Pa used starship shop on the Citadel or something. What he has is impressive, powerful enough to influence governments, and rich enough to construct the one of the most expensive and advanced starships ever built by humans. I mean, come on.