You might notice in the movie that Doc Brown doesn’t lament over his loss of family fortune, mansion and estate. He’s basically too busy enjoying himself, rightly so. He’s knows the rewards of time travel far outweigh such financial matters and material losses.
He is kinda leaving it to the eleventh hour though, having ploughed everything he personally has into time travel, but what else can you expect of a crazy inventor that the mass ego of the official science community and Strickland has chosen to ostracise. Their loss, not his.
Burning questions can’t help but put fire in your belly, and time travel is one of those burning questions. At some stage in the proceedings, just as there was a space race, there will be a time race, and as it hots up don’t be surprised if you see around you such financial changes and material losses but on a world stage. For many this process of adjustment may seem a negative situation, but for those who are interested in time travel it comes with the territory, and often expected.
This part of the process can be likened to the phoenix mythology which rises again from its own ashes, knowing that it has to seemingly diminish before it can be reborn in a whole new world of experience.