All that I can offer is an opinion, and probably not the one that you would care to hear, but while I can totally relate to your desires, because I'm getting along in years myself, I wouldn't care to own or use a computer that relied totally on Cloud services.  I'm not saying that it wouldn't do the job, and I'm sure that they take whatever security precaution that they deem fit, but I do not trust the idea of keeping my personal data anywhere except locally on my own computer.  
Yes, it does at times seem like a struggle to keep on top of things, but then it is also a way to keep occupied, which isn't a bad way to exercise the brain.  I got into computers quite late in life, so I have a lot of learning to do yet, and I doubt that I will ever fully master all things cyberwise, but it doesn't keep me from trying.