My thoughts based on years of representing such companies:
1. Non-funded startups typically don't have employees or, if they do, they are employee-founders. If the cash isn't there to support salaries, you won't have payroll. People can and do get misled in non-funded companies, though it is the rare exception and by no means the rule, since most of those involved understand they are taking a flyer and that nothing may come of their efforts unless and until the startup gains sufficient traction at least to get funding.
2. Most of the abuse involving outright misrepresentations concerns funded companies that hit hard times and then tell their employees that they must stick with a failing situation, and endure the accompanying hardships (missed paychecks, etc.), in the name of deferring their reward until the company can rebound. In such cases, employees are in effect being asked to take the risks of founders and yet are often given nothing more than their deferred pay in case the company does bounce back - that is, having taken on an indispensable role to enable the company to save itself, they get no additional equity or other reward for the hardships they undertook.
3. Funded companies also are more prone to mislead employees with tall talk about what the company will supposedly do and why the options held by employees will be worth so much. Yet, in doing so, they don't tell their employees anything about the capitalization of the company itself, thus leaving the employees with a sense their 50,000 options or whatever will make them rich while in reality they may represent only a miniscule percent of the company and have only a small upside even in a success case. At the same time, no one is ever told about VC liquidation preferences, which can easily be used in many cases to wipe out the interests of the employee-shareholders in an instant as soon as anything goes wobbly with the company.
4. Opportunities come and go rather quickly in the startup world and it may just be a simple fact of life that employee tenures will tend to be shorter in such an environment for reasons having nothing to do either with flakiness or opportunism on the part of employees or with deception or abuse on the part of employers. I think it is a mistake to overstate this in either direction in seeking to ascribe generalized motives to one side or the other.