(It is not only about being able to read.)

From what I understand the optimization can go in various ways, and this includes the rendering and the font. If you have monochrome (Kindle is) you pick different rendering optimization than when you require a high contrast, or you optimize for LCD instead of CRT. So the smoothing and hinting you pick are very important, and if you take contrast into account this might even change in the case of different light situations (sunlight, dark, ...).

Do you know why the letters become too small to read? Because inherent to fixed width font is that it is optimized for fixed width first and then for readability. So you'd need a higher font size with the fixed width fonts. In my experience terminal applications have a too high default font size, but YMMV. Some people prefer a higher or lower font size than other people (because of disability or age or simply preference). Same true for font preference (but there are obviously very stupid choices which can be made in this regard).

Now, if youth are able to use a 3.5" correct and without problem while elder are not we might have a special market for those elder. The Nokia N900 O-Series (for Old people). I doubt it will see the light though. So perhaps you need a different manufacturer. Or like everyone else you need to see an ophthalmologist and get yourself a pair of glasses for reading texts. Or you continue to whine about your disability without solving the root of the problem, making your problem someone else their problem as well.

Also, the problem lies more in non-English texts. This is about the quality of TrueType fonts in Linux:

The type of screen matters a lot too. You should go to some store and see 2 e.g. laptop products which are very same except the screen. One with glossy screen, one with greasy screen. Each have their positive and negative use cases. While the former sucks in sunlight you can bet its sharper and lighter. Maybe a glossy screen even with its negative use cases would still be the best choice for you precisely for the reason it has a glossy screen.