Sure, I don't necessarily disagree with anything you're saying, and given all that, I still think it is the best chance.
#1: in the short term, the quantity of hardware doesn't matter. If you needed a full data center costing $10M per year, it would still be worth it for some people. The idea is to get into a host that is replaceable, and then you can work on making it smaller.
#2: in the short term, you don't need to run in real time. If you are just trying to survive until better tech comes along, running at 1% means the equivalent of 3.65 days per year: maybe enough to survive until hardware improves. Taking this to an extreme, 100 people could pool resources for protection and tech improvement while staying in deep storage and only running their minds very seldom.
Given the above two points, all that really matters to me is that I can find a way to upload my mind into binary data which I know can be simulated faithfully. All I need is upload, storage, and a recovery plan. If the recovery plan looks like it will take 1000 years, fine, I still prefer it to nothing. If I think there is a 1% chance of success over the next 1000 years for immortality, I believe I will do it.
#3: we know for a fact that the functionality of the brain/body is achievable in the space/power envelope of the brain/body. I could easily tolerate a 100x space and power increase. The human body is approximate 100 watts and 100 litres. So 100x is 10,000 watts and 10 cubic meters: 13 horsepower and the size of a compact car -- fine by me. I think I could survive immobile and incorporeal for 100 years with a good library, if, for example, I had to be anchored to the seabed somewhere and run off geothermal energy. The more you expand your lifespan, the more options open up. If you can run yourself at very slow speeds an immense amount of options open up.