This could have the effect of prolonging the period of uncertainty and preventing the recovery of the markets.
In addition macroeconomic fundamentals are still weak or, at best, show modest growth. That is not an environment conducive to rapid recovery of equity prices.
Contrast this to a black swan event such as the earthquake and nuclear disaster in Japan. There the Nikkei lost 16% but fully recovered in 4 months. Recoveries by markets from Brexit may well take much longer.