> it’s not likely that the skills you have on day one are the skills needed as the company scales to the next level.

I don't really buy that this is a major issue. Founders and early employees tend to share very similar skill sets, and yet it's standard practice for founders to get put into c-suite level roles, while it's much more common for early employees to get pushed aside. In some cases it is probably warranted (as is occasionally removing founders from CXO roles) for performance/skill/fit reasons. But I think a more common issue is that early employees are just poorly prepared to navigate the 'politics' that inevitably emerge in a growing startup. There are a few likely reasons for this, in somewhat chronological order:

1. Most founders, from day one, are preparing for a leadership role. This may not be obvious to the early employees, but the founders are probably reading/studying leadership and management material. They are highly likely getting advice and mentorship from other founders, executives, and/or VCs. And they may even have a paid executive coach. Early employees rarely get this type of advice/support/encouragement.

2. No company or startup is free from 'politics', even early stage startups. But early stage startups can trick you into thinking that they are. The org chart is non-existent or flat, early employees work alongside the founders, and every one is working on critical projects. In BigCo, employees navigate the politics by choosing their projects carefully, presenting their work in the best possible light, and currying favor with the right managers. In a fast-paced early stage startup, it's hard to do any of that. Projects are often assigned to whomever has the most bandwidth. And the nature of early stage startups mean a lot of these efforts are going to be wasted and/or failures (usually due to reasons beyond your control, i.e. product market fit, etc..). Ideally this early-stage chaos doesn't get held against you when it comes time to promote people, but that leads me to point 3...

3. As the company starts to grow, the primary motivations of subsequent hires will likely start to shift. The earliest employees are probably more focused and excited about building a product. Later employees are more likely to be focused on their careers. So while early employees are tied down with fixing obscure bugs and supporting and maintaining legacy projects, the later employees are busy playing the political game, i.e. picking cool/exciting projects, spinning everything into big wins, and scheduling lunches/meetings with the founders any chance they can get. And at some point, the start up is going to reach a size where some hierarchy is needed, and before you know it, promotions are getting handed out and you aren't on the list. Which then leads to point 4...

4. Ideally, your newly promoted colleagues should realize your value to the company and seek out your input and participation as much as possible, right? Wrong! Your deep knowledge of the product/stack/company is more or less a threat to them and their new found authority. Even if you make it abundantly clear that you don't aspire to be more than an Individual Contributor, you will find yourself getting left out of meetings and pushed more towards legacy support. And of course, this behavior puts you at a severe disadvantage for subsequent rounds of promotions.

I think what it really comes down to, is that companies are inherently political, no matter how small or large, and it feels like in addition to poor pay (relative to risk) and long working hours, early employees also carry significant 'political risk'. The founders have plenty of leverage to keep their own positions secure, and at the same time they are incentivized to hire the fanciest resumes they can afford (Stanford MBA's, ex-googlers) into management roles to make the company look attractive to VC and acquisitions. My advice to early employees out there, is if you want to grow with the company, you need to start preparing from day one. Get yourself on the winning projects, treat the founders less as colleagues and more as judgmental managers that you need to constantly impress, and spend some time working on 'road maps' and 'hiring plans' to show off your 'managerial' skills. Or just go the easy route and start your own company;)