While Davidson & Buemi are former F1 drivers, they were in backmarker/midfield teams. Even in F1 there's not much press to be had from driving slow cars, unless your team's on the brink of financial collapse of course
It's easy to pin it all on Bernie (and it wouldn't be far from the truth), but as Alex said he had some help in that regard. Most of the manufacturers at that time wanted in on the F1 gravy train.
Even though people are turning off from F1, it's still a big leap to assume a significant number will take to the WEC instead. I know I did, but I may be the exception that proves the rule ... People aren't turning up to races or watching live broadcasts, but these made-for-tabloid headlines still make for good "water cooler" conversations.