We went through something pretty similar in our house, so I get both of your concerns—especially the power outage part and how much space these things take.
In our case, we replaced an older unit with a newer stairlift from a local provider, and there were two noticeable improvements. First, it runs on a built-in battery, so it still works during power outages. That alone made a big difference because we didn’t have to worry about someone getting stuck midway.
Second, the newer model is a lot more compact. It still takes up space (there’s no way around that completely), but it’s nowhere near as bulky as the older ones. When folded, it leaves enough room to move up and down more safely without that awkward leaning or squeezing past it.
We also looked into alternatives. Things like motorized grab systems still require the person to walk, so they didn’t really solve the problem. And single-person elevators were an option, but they were way more expensive and needed structural changes.
So if you’re not planning major renovations, a recent stairlift model is still probably the most practical solution. The tech has improved enough that both of the issues you mentioned are handled better now, especially if you go with a recent model.