I can't be precise on this; but I can give some anecdotal evidence.
I've home roasted the same basic "house espresso" blend for about four years - Brazil base, aged indo bottom, DP Ethiopians on top with a pinch of WP if I need it. This is my comfort food, palate rester blend, when the SOs and experiments get out of hand.
Upgrading grinders and lowering the inflowing air temperature on my airroaster (PID and insulation on the roast chamber) has at each step allowed me to roast bit lighter and a bit faster while still avoiding the lemonpeel effect. This has upped the sweetness and the clarity of the flavors.
Another upshot is that I've gotten far more picky about my blending coffees
However, I have not really noticed much change with brew temperatures; although this is not the sort of blend that's too picky on this score.
In essence, I think roaster/blenders end up making a series of empirical accomodations to their espresso testing equipment, and improvements in these. If the equipment duplicates that of their cafes and clients, they'll be making these accomodations in the right direction. If there's a wide variety of equipment they are not testing their blends on, they are bound to get a few less than joyous surprises.