The answer to the OP is through a combination of torpor, lack of vision, lack of confidence, bad luck and circumstance.
Point zero on this is Hillsborough, The Taylor Report, and the inception of the Premier League and the money that has accompanied it. Some clubs relocated (Arsenal), some redeveloped (Man U) some took advantage of windfall opportunities ( Man City, West Ham) some took advantage of regeneration moves ( Stoke, Sunderland). We dithered.
As football became more popular, as more money came into the game, and as population growth bit such moves produced the doubling of attendances in some cases ( Sunderland), growth of over 50% in others ( Man U, Man C, Arsenal). Such action redefined, by attendance and match day income, the status of many clubs ( Reading, Swansea). We were content to let the market fill our remaining seats and inflate our ticket prices with an attendance growth amongst the worst in the North West.
A relocation was generally unpopular with our support. But in my view that was more down to the lack of vision and confidence in a move than the benefits of staying where we were. Tradition? If you look back long enough we are at Everton’s home ground. A generation has never seen a league title win at Anfield. Today creates tomorrow’s traditions.
In another thread I have seen Peter McGurk argue in favour of the longevity of reinforced concrete. In this thread I have seen Alan X argue that an 80,000 seater would price out fans. I have seen others anxious that we pay off a new stand in five years rather than look at whole of life profits.
Football is a business- but with some very odd business practices, including routinely paying out more than half of income in wages and the most significant growth coming from windfall TV rights, not success on the field.
The latest projections for the season just gone are that we will be £100m ahead of our nearest PL rivals for income (Spurs). That would pay for a new ARE in one season – and still not alter our ranking competitiveness in the league.
That our stadium torpor has cost, and is costing, us dear is not simply financial, it has also coincided with our league failure, and recently sporadic CL performances.
To Peter McGurk (earlier), I would ask, perhaps the ash, cinders and railway sleepers on the original ARE had a bit more life in them ( And a roof? Who needs a roof?)? To Alan X (earlier), I would say that a football ground is not a pleasure park. It is a place where supporters gather. Yes, they will pay to support, but also the club should pay to provide them with the opportunity to do so. The Club can afford it. The windfall growth in TV rights alone would cover the cost of admission for everyone for a season. Now I am not arguing that we should do so. I am arguing that the slavish adoption of corporate business to maximise income at the expense of fans, when that business can afford not to do so, is a curious position for any supporter to take. Some fans behave as if they are the secret love child of Ian Ayre over unsold seats. I can assure you that in the 70’s and 80’s, there were not worried discussions on the steps of the Kop about empty seats in the main stand and gaps on the Kemlyn lower.
I was at Wembley for the Barcelona game. There were nearly 90,000 there, apart from the Barca staff they were nearly all Reds. That is a measure of what our Club is capable of. Yet I have seen some posts sneering at tourist/part time/plastic/whopper fans who have had the temerity to turn up, unversed in match going ways… because, for a change, they could get a ticket!
I welcome the new Main Stand, but will not be celebrating the few thousand extra seats for ordinary fans after the corporate/premium seats have been filled. And with West Ham leapfrogging us in the capacity rankings ( with only 2000 fewer season ticket holders than our entire increased new capacity), and with Spurs and Chelsea set to overtake us with their redevelopments our relative status decreases.
Does capacity matter? I think it does. It reflects status. We are at the top table of EC/CL winners, yet our stadium comes way behind those whom we see as our peers. And we have lost much ground that financially we may never be at that top table for any length of time again – but what we do have is support. A support that is still the second highest by average historic league attendance in the English leagues. Providing an opportunity to come together, even if the team is not firing on all cylinders, cements that support. If you don’t, they will go and do something else, or somewhere else. Man U and Man City have not simply acquired 50,000 extra fans between them in the PL years from existing support, they have provided the opportunity for new support to arrive, as anyone who is on the M6 northbound on a match day can testify.
That is why we are where we are.