There's more success metrics to take away from a startup than just sticking around and creating a 3x or greater monetary return from an initial arbitrary valuation. If you were funded, you were getting paid something, if you were attempting something VCs funded, you were most likely trying something on the cutting edge in which case you are sure to have learned something novel in the space you will most likely to continue to work in.
Consider going to work for any other company, let's say a publicly traded one for simplicity - if you work there for 5 years, and the stock price stays flat adjusting for inflation, is whatever you did objectively non successful? Of course not, in this case you would judge your success based on what you shipped + your own career growth. I don't see why you should look at it any differently from a founder or early startup employee perspective in retrospect (though believing this before starting is probably not healthy as if you believe in the VC recipe you should really be abiding to success as a forcing function).
For 100% bootstrapping to avoid "pandering to VCs", your success metric is narrower (you have to achieve monetary success in a rigid, often short, timeframe) and your risk threshold is lower thus the successes on the learning side/pushing tech forward are less likely.