Ultimately, what put Sukhoi on a path to success was India shelling out the money for a mass order of the Su-30MKI, a true next-generation variant that Sukhoi leveraged to further sales (most Su-30 variants are based on the MKI) and also just plain made them a lot of money off of directly.
So why them instead of Mikoyan? Well, I suspect Sukhoi had a better marketing team. Sukhoi had also had more opportunity to put in design work towards advanced Flanker variants. But also, the Flanker fit the open niches in the international market better than the Fulcrum. The MiG-29, as a middleweight, was competing directly not only with the likes of the Mirage 2000, F-16, and F/A-18 (and later the Eurocanards and F-35) but also against the masses of older single-engine fighters. The Flanker, meanwhile, stood alone as the only heavyweight that could compete with the F-15 on the market, making it attractive for anyone not looking to align themselves with the United States. That's not to say the MiG-29 hasn't sold, but there hasn't been much interest in heavily upgraded variants and no big money-making orders to fund the upgrades themselves.
Your list of prospective customers kind of illustrates the problem: plenty of small orders, but ultimately that looks like only enough new sales to clear out the extra feedstock early. Syria and Libya sure as hell aren't going to be able to fund a next-gen Fulcrum. A lot, I think, depends on what kind of plane Iran wants.
Now, maybe these extra sales do get the MFI flying, but without a launch customer that plane is still dead on arrival. The Russians don't have the dosh; China would, but by the time the MFI is flying there's a rock fight ongoing between the two over the Su-27/J-11 sales; and India I don't think would be able to fund it on their own.