Well, it's only considered an 'inflated' price if you haven't bought into the premise. My take is all the involved parties have an unspoken understanding that 2nd contracts for starting QBs are around 15% of that year's cap. (It seems like they've all bought in since in practical terms it's been that way since 2012 ...)
It makes it easy to budget years in advance, it avoids discussions about whether 1 QB is better or worse than another. And so you end up with nonsense like Wilson and Garoppolo getting comparable deals despite the great disparity in their accomplishments.
It's not unlike rookie deals under the prior CBA. You pretty much knew what each pick was going to sign for: just look at the comparable slot from the previous year and adjust for inflation. And to be clear, I'm not advocating the current system. It reminds me of places I worked where seniority was the primary factor in deciding who got promoted. It was an easy way out for management since saying 'the other candidate has been here longer than you' is an easier conversation than 'the other candidate is better than you'. The downside in both scenarios is that the rewards are not always in line with one's accomplishments.
I've thought for a while that this whole 2nd contract thing is at the root of Prescott's negotiation with the Cowboys. Wentz and Goff's extensions don't kick in until 2021 and are based on a cap estimated to be around $215M. Prescott's deal starts in 2020 when the cap is $198.2M. If Prescott got the same deal Goff did (15.58%) he'd get a 4 year, $123.5M contract, just shy of $31M a year. I'm not sure what he's asking, but the rumor mill says more that Goff's $33.5M. And since $34M turns out to be more than 17% of the cap it becomes obvious what Prescott's real problem is: his agents have not bought in to the 'around 15%' norm.
AlbaNY_Ram