You skipped a few steps. If it's not the fastest, then other companies wouldn't go bankrupt, since they're offering something better.

I.e. it would be the only option only if other companies bring nothing better to the table.

So we should have worse, more expensive internet instead, to keep people in positions that aren't necessary? That seems like a terrible idea. Presumably a Labour Manifesto with this policy in it, would also include a bunch of provisions for unemployed people.

By that logic, we should ban the internet altogether, and thus create more jobs for postal workers.

I was using the words of the comment I responded to. If the fibre was of inferior quality, that would be the space for other companies to compete in.