I think it's a différent situation depending on where you are right now. I don't need to book a flight, and I'm very happy to camp. I think I've spent more nights in my tent than in a dormitory anyway. Coming from another continent is a whole other story. I can cycle down the drive, wander down the Tours route and either jump on a train home or ride back a different way. Then do the Spanish part later if the internal border is closed. As my crystal ball is away for re-chroming right now I'll just wait and see what happens. In the meantime I'm buying a new tent and contemplating a new sleeping bag. Though I have yet to find one that I want and that doesn't require me to sell my family into slavery.
Those who need to plan months in advance have my sympathy. I'm currently hosting a couple from the UK (in the friends house next to ours) who were spending a year house sitting in various parts of Europe. They got to the Spanish border just as it closed, and are now waiting until things open up again, as they have commitments to do other house sits. Maybe not, as the people they are committed to might be blocked as well. As their van carries pretty much all their belongings and their two dogs they are pretty much stuck.
I think maybe the lesson here is not to go any place you aren't prepared to stay if the situation changes.