Another solution is a custom style sheet. Opera has had that capability forever, since about 2001. I use Opera for most browsing, with a custom style sheet to force all text to a certain font and style. This varies by device: Calibri 12pt is the most readable at work where I sit close to the screen on a smallish monitor, while Verdana 12pt works better on my home desktop and laptop screens. My stylesheet also forces text color to black-on-white, very useful for some forum sites that seem to like the scary gothic gray-on-dark look.

There won't be any magic bullet solution. Specifying text size in terms of pixels gives you tiny words on super high resolution iDevices or even modern laptop screens. Specifying size as an absolute via points or inches/cm doesn't work for users lacking the visual acuity to see that size. Specifying size relative to a user-settable device default only works for users savvy enough to find that setting. What we've got now is a mixmash of the above, where devices treat an absolutely-specified size as a baseline to scale from via zoom controls.

But hey, web font scaling is still twelve parsecs better than the original option of going out to buy the large print edition of whatever you want to read.