You've actually asked several questions in your OP.
If we define "the future" as meaning the entire probability set of multiple futures, then we've done away with any specific determinism (although we are still assuming there will be a future of some kind, which of course we do not really know). Thus I would answer your primary question with a simple "No" or at least "It's inconclusive" because it's easy for me to infer this definition of the "the future" from your example statement.
However, your latter question is what I think is most interesting. You asked:
Does language in this case reflect the speaker's beliefs?
To that inquiry, I respond "Yes". This is primarily because I think we are always revealing our beliefs when we speak (a pat answer I admit). However, when I think of the possible unconscious beliefs operating when someone makes a statement such as...
In the future, everyone will have access to clean water.
...I see some underlying considerations including:
- "I believe there will be a future."
- "I believe the future will be qualitatively better than the present."
- "I believe clean water is qualitatively better than dirty, grey or no water."
- "I believe that sustaining and qualitatively improving human life is a valuable teleological objective."
These might actually be beliefs the majority of us humans share. I simply thought it might be helpful to look at some of the implications in your example scenario since you asked a question about beliefs.