Not to worry, I don’t mind being disagreed with.
First of all, if the wheat is yoshon, then there is no need for a heter, it is muttar. There’s nothing to say about it. For those who remember, after the US and Russia reached a nuclear agreement in the 70s, the US obligated itself to buy huge amounts of Russian wheat. This in itself caused so much of an oversupply of wheat that by the time it came to market, the probability that it was already yoshon was very high indeed. Halachic problem solved.
Second, I suspect that yoshon was not available in the spring before Pesach in the Rama’s and Bach’s time. I will check this out with an expert in the history of agriculture. After Pesach this problem dissolves of course, until the next season.
Third, I do believe that “klal yisrael works like that”. Whatever halachic casuistic pyrotechnics that are necessary in one era can be rejected in another era. This does not reflect on the spiritual level or merits of any given person or group at any time. There are numerous examples of this if you go through shutim of previous eras. If yoshon is readily available nowadays, I believe that the Bach’s explanation can be rejected and I believe he would reject it also. This does not mean that anyone was over an issur d’oraiso ever. Al pi hatorah asher yorucha.We do the best we can under the circumstances. That’s what the Bach did and that’s the best we can do. HKBH has it figured out and there’s no need to worry about it.