To my eye, the accents in the examples you provided look mostly like they are already left-aligned but the difference being that they are elongated compared with this screenshot from Dorico.
Many of the examples are not entirely left-aligned. The first example, has several accents that appear a little over the left-hand side of the note – often more aligned with the ledger line.
In the 3rd example, the accents clearly go past the stem, even if they still sit a bit more to the right.
I’d agree that the larger accents inevitably raise questions about their position that narrower accents don’t.
Ted Ross says accents should be two spaces wide, though his examples don’t look it. They should be “vertically aligned with the notehead”, though it’s unclear whether that means left or centred. His examples look centred. (p. 129).
Are we sure that accents didn’t become smaller and centred before computer engraving?
Yeah, I don’t think computer engraving had anything to do with it. Many of the classic notation texts like Read, Ross, and Stone all pre-date computer engraving and show centered accents.
The Music Symbols editor won’t allow an X modification to be made for a single glyph, but if you input a blank space first, then you can modify the X offset for the next glyph. Below I used the Finale Engraver accent, which is a bit longer like some of the examples, and specified a 2.5 space X offset. It looks pretty much left-aligned to me.
I said this was a common practice, but not a universal practice. E.g. Peters used wider accents, but centered. Other publishers used narrower accents.
Ted Ross described mostly the American practice, which was quite different from European. Computer engraving made the centered accents the default, effectively loosing the nuance.
All 4 of those notation books I cited were written before the computer notation era. The computer era may have continued that trend, but it pretty clearly was already the default style by the time notation software came to be widely used. Sticking with a strictly European guide, Helene Wanske I think is saying (in what is basically the Schott style guide) that either way is cool.
Not sure if this is helpful or not but using Finale Maestro or the Sebastian fonts, the accent symbols are just a tad longer than what I have as default using Bravura font.