The path to liquidity is not always straight up and to the right. Some funding rounds can drastically revalue prior shares through reverse splits. This can make your 1% stake magically turn into a 0.05% stake in a single funding round. Even if they don't reverse split, funding rounds issue new shares which is dilutive if you do not also get an additional grant. Once you leave a company, your precious few shares get diluted and reverse split with all the funding rounds between your departure and the liquidity (IPO or acquisition) event.