You can do everything you need with Plain windows and a few other bits of free software.
Cost - moving away from any network to new one is not cheap and cost involved
What is best for school - Maybe plain network is not right move for the school what is good for you may not be good for school.
Technical staff may have other roles and focuses so having middle ware solution like RM is useful.
Time it takes 8 weeks to install have fully functioning network with no issues so of us just don't have that time.
Hi adeasha. Check out the "To RM or not to RM, that is the question..." thread. Also Soapyfish made some pretty good points above. Cheers, Col