Well, I do fly enough - just that I often do it with different airlines. For example, I am flying to Finland next month, Germany in December, and starting in January I do my trade shows - 8 in the USA in CA, WA, TX, AZ, IL, FL, GA and OH. I live in MA so that's a fair amount of flying, although it may not come out to 25k miles unless I focused on getting it all with the same airline, and then often I'd be paying much higher ticket prices or flying sub-optimal routes just for the miles.

On the other hand, if I can get platinum for life just by routing purchases I would be making anyway through specific credit cards, why not?

For the 10 or so times that I fly a year, bumps to first class would be nice, as would quicker boarding and lower prices on lounge membership. Additionally, with that many miles I'd likely get two RT 1st class tickets a year, or I could take a European trip 1st class each year - not bad for $$ I'm spending anyway.