Your assumption that the architects imagination and the clients pocket are at opposite ends of the scale shows in stark clarity that you do not understand what an architect does. You assume that there is nowhere that an architect can add commercial value to a clients business. I pity any architect who finds himself working in that kind of environment.
Short term commercialism is endemic in business in the UK (and in the developed ie., post-industrial nations) today and is not the sole province of the commissioning client. I would have thought you would have more sympathy for that.
In terms of the matchday experience, a fan might be inside the stadium for two hours (and thats where hes going to spend his money). While the outside is emblemic of the pride and value placed in the team, he will rush past the outside to get in on time on the day. The idea that the inside is just a bunch of seats and boxes in a regulatory-compliant arrangement (and shove in some rooms to sell beer - its ok, people will queue for toilets or better, piss on the wall) shows a very poor understanding of what it means to watch and actively support a football team as a valued contributor to the teams (and the commercial owner's) success.
I commission architects and recommend them to clients. Your assumptions are characteristically flawed.
A key part of the architect’s role IS to add commercial value to a clients business, that is what they are paid for. Almost all architects commissions are within strict budgets. Don’t pity those who cannot perform within those constraints- they are not working.
Short term commercialism in design and build always has been, and always will be, with us. Various past era’s though did have one eye on legacy in grand projects, the Victorians being a good example. More locally, and recently, the Liver building also reflects that. Such projects invariably reflect confidence and vision, both are in short supply here at present.
You are right that the outside of the stadium is your statement to the world. Your grasp of the rest, less so. The inwards are indeed primarily a money generating space, the pitch side elevations though to me are vital, they represent the soul of the club where the team, and the fans, unite.