While I dislike Epic as much as the next guy, lets put taste and emotion aside: they went with Epic because Epic offered them a truckload of money. Presumably, enough money to offset any sales lost due to being limited to EGL temporarily, as well as gamers who boycotted the game for the time it was an exclusive, and presumably, no other publisher was offering them as much, or if they were, there were probably even more downsides.

If there was a more financially sensible choice for Remedy, I guarantee you, they would have made it. People have to remember that video games aren't just passion projects meant exlcusively to please fans, they're gigantic, expensive undertakings, surrounded by a massive industry that functions with as much bureaucracy and red tape as any other indistry.