Right, barring some pretty extreme exceptions, such as a king, or a world famous hero dying in some terrible fashion that leaves them more than incapacitated, most "deaths" in the world are going to be pretty low impact for players. A single spark of life, if none of that spark is lost by dying or some other penalty during play, should last you the better part, if not all of, a real-time year.
A normal, average, player without a lot of fame should be able to die scores, maybe even hundreds, of times without losing so much life that it's an instant game over. Now, you will lose some play time each time your character dies, but in most cases we're talking hours, or a day, not weeks or months. It will wrack up in the aggregate, but generally speaking no one death will take so much play time that you need fear spending more money any time soon.
As others have pointed out though, as your fame or your infamy grows, the costs of those deaths ramp up. If a queen sallies forth to slay some large terrible beast, and that beast ends up eating the queen, it's possible for the queen to lose as much as 25% of their total play time from that death, if they were a well known and well like/well feared monarch. In a similar fashion, there are certain acts you can perform that the game system views as "dark" - when you perform these acts there is some cost to your character's lifespan. So if you're a disruptive griefer, you'll find you need to create a new character and invest a new spark of life far more often than a player that doesn't act to negatively or maliciously disrupt the normal course of play for the world around them, though admittedly not to the extent that fame or literal infamy will affect playtime.
So, I suppose it's a mix of "it's not really like that" and "Well, it's a little like that" that we have going on. It's definitely not a pay to win game in the sense that you can just go to the cash shop, buy a potion of ass-kicking or a suit of impervious armor and then be better than your fellow players, though. When the game launches there will be no cash shop, and while the promos we run prior to launch do allow players to start with certain items, or the means to produce them, already in hand, nothing we're offering is unobtainable through other means.
But, to your main point, if you have the money to buy more sparks of life, there's nothing to stop you from sparking into a new character. The good news though, is that new character won't have everything the last one did by default and it will be starting young, meaning it can't just jump right back to what the old character was doing without first developing itself up to the same level. That means that instances of players "throwing money at a boss" until they finally beat it or something similar should be few and far between (and will definitely take longer than anyone trying to do it would like, i'd imagine).
Hope that helps! :)
Vice mayor of