Hi Rolf,
Sadly, I don`t think the ITA could do anything to grow the weekend sailor base in the class. The boat has been refined and developed into a Formula 1 race car,in order to retain it`s Olympic status. Not too many folks would buy a F1 race car just to go weekend racing at their local track.
Of course I was exaggerating a bit when I said the class would disappear, but the truth is that most top-level T sailors would move onto the next class chosen for Olympics, even if it were the Hobie 16 without spinnaker, as the Olympic medal hopefuls are there for the medal, not the boat. The class would suffer a huge loss at the top-end, and many lower level (mere mortal weekend) sailors would pursue a more affordable class such as F18/Hobie Tiger/ F16/whatever the stronger classes in their own country are.
The Tornado would still exist in wealthy countries, mostly in Europe, but in developing countries other more affordable boats with more local involvement in the manufacturing process will be easier to sell to an already diminishing participant base.

The typical scenario in South Africa : The Dart 18 Worlds in 1999 were in SA, many Hobie 16 sailors bought a Dart just to do the event, so the class grew rapidly, but the hobie class suffered low turnouts for a year up to the Dart Worlds. Then Tornado Worlds came around, so many of the Dart & Hobie sailors swapped allegiance, sold boats & bought Tornados. The Dart class suffered a drop in club turnout from 28 boats to 4 boats at club level at one club alone. In 1999 you couldn`t find a Dart for sale, while in 2000 you couldn`t sell one. Same with Hobies before Tornado Worlds. Now the 10 or 12 Tornado owners would struggle to get the correct value for their boats if they wanted to sell them, because there is no REASON for a demand.
Dart Worlds AND Hobie 16 Worlds are both in SA in 2005, will be an interesting time just after these regattas - I believe there will be a lower South African turnout at both, since sailors will not be jumping classes as much, maybe more stability in the resale value of boats will be a positive outcome. my point is that many Tornado sailors would possibly switch classes if the boat lost Olympic status - not because they have hopes of competing in the Olympics, but because it`s nice to own a boat that has recognition. I think F18 or F18HT will benefit from this if it ever happened, since the boats are easier to transport & cost a lot less to maintain and campaign for a Worlds. At present, how many boats does the Tornado Worlds attract ? 62. Still a fair number by all means, but not when compared to the Dart 18, which attracted a "poor" turnout of 102 boats in 1999, normally over 150 boats up to 300. The cost of sailing a boat is critical - most Dart sailors, even at Worlds level, are just weekend sailors with enough cash for an overseas holiday where they can go sailing for 10 days in a new location. If the ITA could get the average weekend sailors in their class to the Worlds, half the battle would be won. The reason that weekend warriors would feel out of sorts at a Worlds is that the boats have become too expensive to keep up with the top guys. Rig changes, carbon masts, and high-tech manufacturing methods have elevated the cost beyond reach of most.
With Olympic status comes professionalism. Competitors are paid in one form or another to train, compete & sail 8hours a day every day. It`s not sensible to expect a weekend sailor to even attempt to keep up with that. So we find that all Olympic classes lose their weekend sailor base at Worlds & even Nationals level. Once the National level has been eroded to a handful of sailors (Only 20 in Germany, you say?) that are really the guys trying to qualify for their country`s spot at the Olympics, you find that at club level the class suffers, since a Nationals is no fun for a regular sailor when competing with the Olympic hopefuls.
The Finn and Star classes are examples where the Olympics have kept the classes alive longer than they should have survived, they are both fairly antiquated classes in todays terms. The T is far away from that, but has only kept up with the newer designed cats through the rig upgrade (which was forced on them by the Olympic selection committee) and highly expensive manufacturing methods. That, and the fact that the designer got it so right all those years ago.

Sorry for such a long reply, just my thoughts, not necessarily correct, since my opinion can only be based on what I`ve experienced, read or heard throught the grapevine, none of which are reliable sources of information !

Cheers
Steve