The short answer is money, or lack thereof.
This has been discussed several times before, however, it is worth presenting a short history of the effort to get a station in Brevard County again.
The original All Aboard Florida plan was for a four station service (Miami, Fort Lauderdale, West Palm Beach and Orlando). It was not clear that even for this funding could be arranged. But even back then conversations took place about future possibilities. Brevard County has been working in the background with Brightline in station location selection and such. The tacit agreement always was that a station in Brevard County would be taken up after a successful and stable introduction of service to Orlando..
One must remember that this is not a government funded thing where you can hang every bell and whistle on the Christmas Tree from the get go and then go and twist the arms of the legislature to try to fund the whole bloated thing. There was no certainty until about four years back that anything would get built to Orlando at all.
Notwithstanding that, the County Council voted to engage with the then All Aboard Florida folks about seven years back on this and low key activity with full support of the Space Coast TPO has been going on since then. Now that Orlando is in sight I suspect there will be some motion on the Brevard County Station in three to five years. The fact that land acquisition is taking place is an indication that things are actually moving, which is a good thing.