Futurology

It's entirely possible. Actually I suspect Elon might get to Mars and realise it sucks, because he's nearly alone on a barren planet and Twitter has massive lag.

After the moon, Titan is the only place here that seems worth bothering with a colony on. Hopefully we do (some variant on) sleeper ships at some point, because our sun will only last so long, but if there's no dumb billionaires to fund it in the future we might just not bother.

Edit: That said, I wish OP made more of a distinction between cost, feasability and present mature technology. We can feasibly live without an atmosphere, but it might not be worth the cost. We can feasibly reach a few percent of lightspeed, but not with conventional rockets. (Other technologies are mentioned in the footnotes, but OP's grasp of the alternatives seems to be lacking. Fission-electric has working prototypes, we could theoretically make ourselves smaller or more space-hardy, magnetic parachutes to slow down...)

I think the conclusion is justifiable, but the whole thing is a bit sophomoric.