Using a 10% time-value-of-money discount, your stock options are only worth ~35% of their final monetary value when you first start out in the 10-year payoff case. That's not a 35% chance that you'll make something, that's the discount on what you do make. You still need to factor in the risk that you'll get nothing or a pittance, especially if we're talking early startup where the risk that you get nothing is probably somewhere in the 90% range. You don't have to come up with very unrealistic numbers in the current environment before you're looking at applying a ~95% discount to your hopes on what your stock options might be worth in 10 years.
(IMHO, working at a startup when you're young for some hard & fast experience, if you can afford it, is possibly still worth it, but at this point in 2017, early engineers should be demanding either cash or founder-level equity grants. An in-between grant that may pay out $100,000 in ten years may sound grand from the perspective of someone about to receive that payout, but from the front-end you should value it somewhere around $5K or so, and I wouldn't fight anyone who wants to pick numbers to push that lower. On an annualized basis, $5K is more like "a minimal raise" than a reason to work at a company.)
Money today is worth more than money tomorrow, and often the lump sum of money you get at the end of a startup’s liquidity event as an employee is not much greater than someone who earned money through a more traditional route, if you even get it. I know people who chased the startup life for years with nothing to show for it.
A decade later when they finally give up and resign to a more traditional career path, their cohorts who started down that path a decade ago are now impressively far ahead of them in life. I’m talking big houses with long hallways and a baby or two keeping them up at night while they ascend the ranks of a “real” company during the day.
So when playing the startup game, the only thing on your mind should be “fast money, fast money, fast money!”. If you like to see businesses that have been around for way longer than 10 years and building strong revenue that most startups can only dream of, don’t look for startups.
The standard pitch (that many recruiters abuse) was that your options would become real in 4 years but the reality is this is closer to a decade. If companies were marketing their options realistically instead of selling them like snake oil the 10 year point would be fine.
I remember interviewing with an almost unicorn and their VP of engineering literally tried to pitch their options by telling me to assume the company would IPO at XXX price within 4 years. No mention of opportunity costs, tax issues, liquidity issues, etc. He even forget to consider the strike price when "helping" me ballpark the benefit. And everyone seems to forget there is thing called the discount value of cash - $200K in 10 years is not the same as $200K in 5. It's been 2 years since I got that unicorn offer and I can say that the company is at a minimum still 4 years away from an IPO.
Stop selling the snake oil and people wouldn't be unhappy when there is a decade long payout time.
But more to your point, recruiters lie, and if you don't realize that as a grown up, college graduate, you've got bigger problems in your life, I suspect, than when a company decides to file IPO. They shouldn't lie, but recruiters tempting you with options also isn't a reason to suddenly submit to the SEC and public traders to get some cash.
So in practice, employees are shackled to the company until IPO happens.
(Note: some more progressive companies have been combating this dynamic a number of ways -- I don't know if Dropbox is among them)
Customers.