Yeah, Lp that's where I was going. Most people, wisely, get one ski that handles most of what they ski, and here in the east...even at Stowe

, is either groomed, are 50-90% of the time, pretty damn firm. The 75-85mm low to mid-radius ski, that's not too stiff in the tip or tail, serves the masses very well. And skis like the MX78 or the old Head im 78, though they won't carve quite as well as slalom style skis, still carve pretty dang well and won't leave you crying into your beer at 4:00pm that you wished you had narrower skis after a firm snow day.
Any other ski one buys, is a specialty ski. You've gone into quiver mode. The skinnier ski with a race pedigree (if not an actual race ski) becomes very condition specific, and is certainly not 'necessary' to enjoy firm conditions. Just as the Fat/ Rockered ski is also condition specific and, assuming the skill of the user is high intermediate or better, not necessary for enjoying soft snow. Though both make each situation better under a skilled skier.
I like Gary's quest for the Two ski quiver...it appeals to my basic minimalist instincts...and I hate overlap. For a true all mountain skier, the two ski divide won't be a supershape and an S7. I think, they'dbe what Gary has done...a very, very hard snow capable mid fat (the MX78) and a very, very soft snow, crud and tree capable wider ski (The DPS 112). I think a quiver like that is driven by experience derived good sense and not marketing hype.
Last two days of skiing at my local bump were very good by the way. Skied both days with my littlest guy (9 year old)...his skiing has really come along! And he seems to be able to enjoy the whole mountain on a pair of shortish Junior race skis.