We swim in End of Ages to an island on Noloben. We swim in Ahnonay in POTS. The clocktower was closeer to us then what we were trying to reach in those two games. Why couldn't we just swim to the clocktower?

First, I don't recall there being a clocktower in... oh, you mean that cool telescope and pressure plate? No, we didn't swim in Noloben - I think it was more of a wade, no?

And as for Ahnonay - well, swimming to something that is not hidden and is not far away isn't so exciting, now, is it?

Because the water in Myst is acidic, and you couldn't swim in the original game .

That, and because realMYST was done in 2000, while PotS and EoA were made in 2004 and 2005 .

Because you originally couldn't swim, but as you started traveling ages, it beamed itself into your brain!