Sports such as international tennis and domestic rugby are already at this point. In the few years since satellite television began bringing tennis' grand slam tournaments to a global audience, the numbers actually attending on most days appear to have dwindled.
Crowds at Super 15 rugby matches in this country are certainly challenged. The scramble for tickets to the final at Waikato Stadium tonight is a welcome change from last week when semifinal seats were slow to sell out.
Even the Crusaders have struggled to fill their small Christchurch stadium in recent weeks.
In one sense, the diminishing attendance at televised sport is perfectly understandable. Nobody in London this week has seen a fraction of the action we have seen from Auckland unless they too were watching the Olympics on television.
The Sky service has devoted so many channels to its coverage that subscribers can follow several events at the same time. When you can get from one venue to another at the press of a button, who would want to face the London traffic?
If world-class sport can pay its way with television - and only with television - why should it care about the crowd? Unfortunately, that is exactly the impression it is giving to crowds these days. Rugby is our only truly world-class sport and it makes little effort for those who still occasionally like to watch it live.
Match information is minimal. Even scoreboards have become hard to find. Frequently the only clock is on a big screen which gives the crowd action replays but constantly reminds them they could have had a closer view from their sofa at home.
It is a wonder, really, that anybody turns up. Yet few sports could last very long on television without a crowd in the background, preferably a happy crowd. It is to be hoped that domestic rugby soon wakes up to the need to improve its "crowd experience".
Last year's World Cup organisation showed the way. The pre-match entertainment and presentation of the games was professional, rousing and good spirited. Crowds for the most part responded in kind.
Live sport has qualities television cannot transmit. Its lens compresses heights and distances. To know the scale of things, the heat or chill in the air, the true pace and dimensions of the action, you really have to be there.
Each empty seat is a missed treat.