The understanding of the gemara I took for granted when I learned it -- and therefore was the "simple" one to me -- is:
Rav (as quoted by Rav Yehudah) proves his point that people who (a) cross the sea, (b) or the desert, (c) are healthy after a potentially fatal illness, or (d) freed from prison must thank Hashem from pesuqim in Tehillim 107.
Nothing about the likelihood of danger is mentioned in the gemara at all. It's scriptural. Something special about these four kinds of situation that gets them singled out in Tehillim.
Leaving simple understandings... I would suggest what that "something special" is If we look at context in Tehillim 107, we get (v. 2-3):
יֹ֭אמְרוּ גְּאוּלֵ֣י ה֑' אֲשֶׁ֥ר גְּ֝אָלָ֗ם מִיַּד־צָֽר׃ וּֽמֵאֲרָצ֗וֹת קִ֫בְּצָ֥ם מִמִּזְרָ֥ח וּמִֽמַּעֲרָ֑ב מִצָּפ֥וֹן וּמִיָּֽם׃
The redeemed (ge'ulei) of Hashem will say -- those He redeemed (ga'al) from adversity -- / whom He gathered in from the lands, from east and west, from the north and from the sea.
People in these four situations not only were saved, but they were saved in situations that provide ge'ulah redemption.
The Gra (quoted in Seder haArukh) also hears echoes of the redemption from Egypt in the chapter as a whole. Although not verse 3 (above) which speaks of an in-gathering from all four compass points. But 106 was about the Exodus from Egypt, and v. 1's "הֹד֣וּ לַה֣' כִּי־ט֑וֹב כִּ֖י לְעוֹלָ֣ם חַסְדּֽוֹ׃ -- Thank Hashem for He is Good, for His Lovingkingness is Eternal" is a recap of the opening of ch. 105, which runs through the forefathers until getting Israel (including the Exodus from Egypt), and ch. 106, which is about the Exodus.
More tellingly, and what the Gra discusses at more length -- these four situations in particular were involved. (a) Crossing Yam Suf, then (b) the desert, (c) we were healed at Har Sinai and (d) freed from Egyptian bondage.
So it seems to me we hold that these four situations, which ought to bring to mind our Exodus from Egypt and the eventual ultimate redemption, require birkhas hagomel. Not because they are particularly risky, but because we should be taking our situation as a source of hope for global redemption.
And then we hold, not from this gemara or Tehillim 107 altogether, that a miraculous salvation from risky situations also require a Birkhas haGomel. Although some say that an abridged version, without the critical elements of including G-d's name or Kingship [sheim umalkhus] should be said. See Shulchan Arukh Orakh Chaim 219:9-10. The Mishnah Berura (ad loc, sei'f qatan 32) and the Arukh haShulchan (219:12) rule that the berakhah should be made in full, the latter adding that this is accepted practice. The Arukh haShulchan also makes a point of including "hidden miracles" in this obligation, not only the explicitly nature violating kind (ibid, se'ifim 3-4).
Side note: The Rosh (Rosh, Brachos 9:3) and his son the Tur (OC 219) understand Rav Yehudah quoting Rav as talking about when one should be bringing a Qorban Todah (Thanksgiving Offering). His words are "צריכין להודות -- must thank." It is "only" when we get to the ammora'im (including Rav Yehudah himself, not citing Rav) that this turns into a discussion of berakhos. Birkhas haGomel is a replacement for the Todah, so the gemara just discusses their common rules without explicitly distinguishing between the two.