The LOI as it is now used is a misunderstood application of poorly informed brokers and traders. A more proper application based on established custom and practice in International trade, going back even to the old medieval "Law Merchant" (Lex Mercantilis) is: Buyer requests a quotation _ in modern usage this is an RFQ/Request For Quotation _ NOT an LOI. Seller may then reply with a Quote. Buyer confirms receipt of quoted prices, and requests an Offer.
So, if a letter or document that nominally or presumably conveys the signer's "intent" or intention to buy, is essentially meaningless and worthless in legal terms, and is not binding on the signer or anyone, and CANNOT be enforced on him, then why would a respectable crude buyer, in the first place, want to waste its precious time and resources (or that of its expensive lawyers) to engage in such a fruitless exercise for the benefit of a seller? Especially for an unknown or obscure seller?