[michaelt]

  The idea of paying for more extensions seems incredibly 
  frustrating. I'd rather know what the cost will be upfront.

Isn't that Altium's existing model? And for all features, the upfront cost is about $7000 per user?

It's not an unreasonable price for big companies (if it boosts the productivity of an engineer costing $100k+) but there's a lot of people who aren't going to spend $7,000 (anyone who isn't doing PCB design full time as a profession). If Altium want to sell something that costs less than $7000 (maybe $200-$500 for a perpetual license like Eagle) they will either have to:

(a) Take far less money from their existing $7,000 customers or (b) Provide a cut-down version that meets the needs of the $200-$500 market without replacing the $7,000 product.

Much though I'd like it if they did (a), I think they're a lot more likely to do (b).