The answer is 100 machines. 1 machine build the brickwork in 3...

The answer is 100 machines.

1 machine build the brickwork in 3 days.
Assume 300 working days in a year.
Therefore 1 machine builds 100 houses per year.
100 machines builds 10000 houses per year.
5 years to build 50,000 with 100 machines. This matches the KSA MOU requirements.

So $2 million per machine.
= $200 million for 100 machines. + ongoing recuring revenue from bricks and maintenance.
The unanswered questions are
1. The cost to produce each of the 100 machines ?
The cost is much less than producing 2 machines, but much more than producing 1000 machines.
and.....
2. How long to build 100 machines ?
Many years if they are all built at Sultana Rd.
If built by CAT depends on how many resources they are prepared to throw at it.
Odds are they would need to spin up new capacity which takes time, as even CAT wouldn't have significant idle facilities that are currently doing nothing.