No manufacture is going to produce large numbers of the simulators required without certainty that the MAX will fly again or a guarantee of payment if it doesn't. Given the lead time required to make the sim, deliver, install and certify it along with training the instructors needed, work needs to start immediately.
A greater number of simulators will be required to avoid a bottle neck if the MAX flies again than will be required if operations return to normal. Even if the simulators are running 24/7 they will only be able to support a phased return to flying, but that shouldn't be a problem as long as they can match the pace of aircraft deliveries and engineering work.
The logistics involved in returning the MAX to service, if it ever happens would require someone with the level of skill required to plan the invasion of a foreign country.