Any chance you could explain this a bit more? Intuitively it makes sense that this would be as important if not more so than the modeling itself, but I have no context for the difficulties encountered when implementing it.
Or your model might need to be really, really fast. Not everyone can just have access to a microwave link. The guys with the microwave are also picky.
Or your model needs certain kinds of data, which you will need to get certain vendors to sell you.
You might have a need to trade multiple models at once, which are not profitable on their own (uncorrelated, share costs). This is a juggling act done often at the business level.
For almost all trading you need some staff who know how to do things. It's not always the case that you just pay them a salary to do some job. Business decisions there as well.