Unless you are the co-founder of the startup.
Also, if you are the full stack marketer of a <10 people startup (where almost everyone is a engineer); you should naturally put yourself in the place of this startup VP Marketing.
Sure, years of experience count if you want to be hired as a VP Marketing at any other company. But a very important upside of being an early employee is the potential to grow with the company faster than you would at a traditional one (the same way the startup itself hopes to grow much faster than the incumbents).
If people are coming from outside to a position higher than you, then is one of two options: (i) you are not as good as a full stack marketer as you should be or (ii) you chose poorly the founders for whom you would work for.
So I would say that that's the bless of being a full stack marketer. If you choose your startup well, you would be a VP Marketing years before someone on the traditional path.
This is the reason to go to a startup as a Marketer rather than P&G. At P&G, even with a top school MBA you'll wait 10+ years to be a Marketing director, let alone a VP. At a startup you'll get the title and responsibilities (if not the budget) much sooner.
Part of it is picking the right founders. How to do that? One is past history. What did they do to prior folks who came along with them? Do they have a history of replacing people with "professional managers" once things start growing?