I really don't think WDW needs very many members to justify the one time cost of refurbishing four areas into lounges and then the continued operational cost of a CM or two and incidentals each day. Any additional members are almost pure profit because the incremental cost of adding more members once costs are covered is nil. Even the perks aren't cost items in the strictest sense, they just have a microscopic effect on capacity.
I am not a Club 33 member, but I have dined there a couple times in the last 15 years and I have had a cocktail at the 1901 Lounge (Club 33 satellite location in California Adventure) as a guest of a member. I think you are misunderstanding the service level and operational needs of the Club 33 concept. It is not just a cheesy corporate lounge at Epcot for Exxon employees to get free Cokes and pretzels.
As one example,
Club 33 requires a full staff of concierges. And not just WDW hotel "concierges" which are just college kids in ill-fitting polyester suits sitting at a desk in the Poly lounge to tell you that the parade is at 3 o'clock and Ohana is fully booked, all things anyone with an iPhone could do for themselves in 30 seconds. Club 33 concierges are actual, real-world concierges that arrange your guests entire Disneyland stay, from VIP tour guides to airport Town Car pickup to a club box at an Angels game and third row seats to the sold out Michael Buble concert at the Hollywood Bowl next weekend.
Then you've got hostesses at the door that pass out seasonally chilled or heated scented moist towels as you enter (to wipe off the theme park germs), a battalion of waiters and waitresses, bartenders and barbacks, the maitre'd, bussers, an entire kitchen staff, management and member services staff, live jazz bands and singers in the lounge, a live pianist in the lobby, etc., etc. It doesn't just take a village, it takes an army of staff to run Club 33 and 1901 Lounge for a day.
Quite frankly, with a $50,000 initiation fee and $12,000 annual dues after that and a multi-year waiting list to get in, I'm surprised that Disneyland makes much money on the whole thing after seeing the incredible level of staffing and service they provide members and their guests 365 days per year.
WDW management has a huge task to live up to the Club 33 service level. It can't just be a nicely decorated lounge with a bored bartender and a random college kid CM checking ID's at the door. WDW already has that middling lounge service with their "Deluxe Hotel Concierge Lounges" and the Epcot sponsorship lounges for every General Motors or Exxon middle manager and his sweaty kids. Club 33 is something very, very different. And it's not cheap to operate.
I assume TDO and WDW management understand what they are getting themselves into with this.