I remember back in the day applying for a job as a young teenager. One of the interview questions always asked back then was "will you be available to work on Sundays; if a shop dared to risk the ire of the community by being open on Sundays. If you answered "no", the employer couldn't not hire you. But it did set you apart from other prospective hires that could make in in anytime of the week...This was back when people took going to church quite seriously and that was taken for granted that nearly everyone did that weekly...
My point being that go ahead and allow the muslims back in on this particular issue. Make employers observe their 1st Amendment right. However, also allow employers to ask the question in an interview "will you be able to complete every normal work day without needing special time for prayer breaks?" If the answer is "no" then the prospective employer knows where to put your application in the large stack in front of him with people who are willing to work through the day without 5 breaks to kneel and face Mecca. Eventually, the Muslims if they want to feed themselves, will either create industries on their own that allow 5 times a day prayer breaks, or they will just silently turn towards Mecca during their two 15 minute breaks and lunch hour to pray. They could pray before work at dawn, first 15 minute break, lunch, second 15 minute break, then again in the evening after work. That equals 5.