While exit strategies might be fewer during a recession, the point of starting now is that the economy will (hopefully) be out of the recession by the time you want to exit (typically beyond 12-18 months).
Yes. Startups generally take 3-5 years to succeed. The economic situation that far ahead is effectively random, so you can discount it.
Just curious, how do you define succeed? Founders becoming millionaires or?
Agreed. With some exceptions, startups are more like marathons than sprints. Investors often look for an exit in ~5 years, while too many founders think that they'll be out, as a success or failure, in 18 months.