I have not done a study of that base, but it still occurs today, although not very frequently. We have seen it in these very ancient games when a player played on the 3-11 point with the 3-8 point as a miai point to make a base. In the early modern era players often made the base with no provocation at all. OC, making this base would usually be slow by today's standards.
I have to disagree on a couple of points.
Not sure what you mean exactly by early modern era, but whatever the cut-off, until the late 20th century players made many moves in consideration of there being no komi, so they may not have been making this shape gratuitously.
More important, this shape is nowhere near as rare as you seem to think today. Taking a generous space, with a third-line two-space extension centred inside an otherwise empty 10x5 rectangle of points based on the sides (to attenuate the charge of provocation from nearby stones), roughly 80% of well over 1,000 games in the GoGoD database that have this pattern can be classed as modern, taking as an arbitrary cut-off point the advent of Go Seigen. Even if you want to restrict it to very recent years it is still very common, and appears without any obvious bias in all the major pro countries and with the usual cast of stars.
If you are counting early Edo as "early modern", with one exception the shape does not appear before 1620 (Dosaku) and is not specially common thereafter in early Japan. It is the Chinese who played it most then.
If you make the rectangle 8x5, it's ten times
more common (almost 15% of all games) and even more so in modern play. Making the cut-off date here equally arbitrary at 1980, 75% of cases are in modern games (Sansa still gets just one).
Not every case can be classed as a base pure and simple, but plenty can (most? - over 90% of cases occur in the first 50 moves), and of course even extensions from a moyo can be cut off and have to fend for themselves.
It's more the third line and pincer width that differentiate the ancients from the moderns rather than two-space bases (see also Fukui Masaaki on this topic).