Earlier quoted context omitted.
Absolutely, you can hack it on a very individual basis, but this introduces some major problems. For instance, browsers and operating systems all render fonts differently, and as the web is fluid by nature, simply having a sentence break to the next line can be an issue. Also, it can be incredibly different based on the typefaces you are using.
then i still don't get it. When a simple line break would break a horizontal baseline-aligned grid, wouldn't it break a horizontal baseline-plus-some-space-aligned grid? Although the css prop. "line-heigt" is not implemented in a convenient way, it is still deterministic as I understand from the quoted article: "This is determined by working out the difference between the line-height and the font-size, dividing…
Let me put it this way, if there was a semi-reasonable solution, I'm sure you would have heard about it.