Oh yes, the opinion I presented is far fom universal, it is still a minority opinion, but I feel it may eventually be accepted in lumdus theory. I have no doubt that the Satmar and others will not give this interpretation the time of day (no pun intended), however strong the argument may be.
The flaw in waiting 72 minutes from what we see as sunset is that there is agreement in all gemara sugyot that bein hashmashot ends at three medium sized stars. At that point, it is night, period. Throughout the year, 72 minutes post sunset is approximately 30 minutes past three-star appearance time. As is plain as one can see, 72 minutes after sunset, especially in the Middle East, is as dark as dark can be, and cannot possibly represent the end of bein hashmashot. Without saying this time-table is ridiculous, it certainly is logically untenable.
A close look at Rabbeinu Tam’s own words (not just quotes in his name in Tosfos and other Rishonim and Achronim) clearly shows that his two-shkiah solution, besides being a stroke of innovative genius, refers to the sun entering the thick corridor (rakia) and still being seen (first shkiah),until there is no light left , significantly after the sun is no longer seen (second shkiah). The end point, though, is three stars and no later. Astronomical/Visible sunset occurs without halachic consequences.
That said, any further explanations on my part would not do justice to the painstakingly thorough treatment the two illustrious rabbonim I sourced above independently gave to this subject. I will allow their published works to convince you. Or not, hakol l’shem shamayim.