It's popular assumption that Ray can't hit the notes any longer. He can. He CHOOSES not to, for a couple of reasons:
1. His range can be spotty on tour, and those early tours for No Exit, PS, and Parallels showed that, so he just stopped doing it.
2. He's just not into showing off, as he's said repeatedly he prefers a more melodic approach.
If you compare Darkness in a Different Light, and Theories of Flight, you'll notice there are spots on Darkness that he could have done some sort of higher note, but did nothing. That shifted on Theories, as he carved out a couple spots for a note for emphasis, but nothing in the stratosphere. In addition, he did interviews in the last five years where he was asked about the range thing and went and showed the interviewer he could indeed still get up there if he wanted to. But for the two reasons stated above, he just doesn't. I am sure as he gets older, he WILL start to lose that ability. So, he was actually pretty smart in the artistic and style decisions he's made over the years.
p.s. just got Live Over Europe. SO. GOOD. I saw the last two album tours three times. Once on the Darkness tour (Dec. 2013) -- should have been twice, but the other was on Halloween and couldn't make it, and then twice on Theories (Jan. 2018). So fortunate to be able to have now seen them a total of five times. (The other two were opening sets for DT/QR in 2003.)