It's not a matter of whether the I1d (L22) branch was ever Germanic or not, but
when it became Germanic.
We cannot talk of Germanic people before the Indo-Europeans moved to Scandinavia. The first wave was the R1a people of the Corded ware in the Early Bronze Age (2800-2500 BCE), but this branch being more closely related to Baltic and Slavic peoples, it is doubtful that it was already Proto-Germanic. The second wave came with R1b sometime between 2500 and 1200 BCE (perhaps several successive waves from Central Europe). I think it is only once R1b came into the mix that we can really talk about a (Proto-)Germanic culture and ethnicity shaping up. The cradle of Germanic "civilization" would thus correspond to the
Nordic Bronze Age in Denmark, southern Sweden and coastal southern Norway, but ultimately expanding from Denmark and Scania.
My hypothesis here is that this original core around Denmark and Scania included only I1-Z58 lineages alongside R1a and R1b (+ minor lineages like G2a, J2 and E1b1b). The people in central and northern Sweden and Norway, as well as in Finland, would have been predominantly I1d (L22) and R1a by the time the true (Proto-)Germanic speakers moved up to from Denmark and Scania in the Late Bronze Age and Early Iron Age (the period circa 1200-200 BCE).
After that, of course, I1d became Germanic. But I am pretty sure that the original core of Proto-Germanic culture never included central and northern Sweden and Norway. I also doubt that all the inhabitants of central and northern Sweden were wiped out by the Germanic expansion. They must have belonged to something, and the best candidate is I1d, justly because it is also found among the Finns and the Saami, who have R1a lineages but very little R1b, and do not speak Germanic languages.