The post you are reporting:
Tendering is a complex process and not easily explained in a post on a forum. But yes, it is sealed bids given after an Expression of Interest and Invitation To Tender. Local firms will have had an opportunity to tender, and many factors may have either led to them not tendering, or to being rejected. Cost - both ways - is one factor, but quality, reputational factors, ability to deliver, and potential risks will all play a part. There will be a risk register that impacts, somewhere. Again, for both sides. Presentations, negotiations, and conversations will push the process further. At any point either side may change their minds right up to contract signing - although clearly that is less likely as both sides invest more time and effort as well as money towards process end.
I wonder what the response would be if a local firm won the tender because of their geography and then screwed up royally and over-charged, created oodles of slippage extending the project and shafted the council. I rather suspect similar people to those on this thread would be crying "waste", and "poor management" then.