M.S.R.Ps. They are what manufacturers think their products should cost given fair market conditions. They are also not iron clad. A dealer is free to charge whatever they think they can get, and a product on the open market is only worth what someone else is willing to pay for it. Lets examine GT86s on the open market, and see why people think they should come with more power.
M.S.R.P. for an FR-S is about $25k. $26k for the Auto. So now that we know how much they cost, we just saddle up and head to the nearest dealer with our down payment in hand, right? Haha. Hoo hoo. Not so fast. Dealers where I live think they should get closer to $27k-to-$30k for them. It's not impossible to get an FR-S for close to - or even below - MSRP if you live within a 50 mile radius of me, but be prepared to do some driving, seaeching and haggling to make it happen. Also be prepared for disappointment; They wouldn't ask inflated prices for the bulk of their stock if they didn't think the demand would allow them to get it.
Want your GT86 to come from scooby instead of a 'yota? Same story, it is. Minus the deals I mentioned before.
The Abarth MSRP is only a bit lower than the FR-S, at $22k, but that does not reflect the market reality. Because M.S.R.P. Abarths are easy to find, there is in actuality a $6k gap between these two cars, which can widen to almost $9k(!) if you do some of that haggling, search and long distance driving I mentioned before.
The Fiesta ST tells the same tale, with a handful of examples actually sitting a bit below M.S.R.P.
Now we have the answer to our question. Why is it okay for everyone else to underperform? Because the GT86 right now is asking a significant premium over it's competition. I cannot say if these market conditions are true everywhere in america, but if they are, it would to me fully explain the 'it needs more power' judgement people render against it. For me, a $5k-$10k premium is firmly crouched in 'why is this not faster?' territory, given what we know about the car, and what it's competitors are capable of.
This is such an easy fix. Add .5 more L, a bit of tuning and some exhaust, and done. 50 more ponies would end (or at least significantly alter) the conversation, without adding a single pound of curb weight.