I beg to differ, and I base that differing on 40+ years in the two-way radio and paging business. Looking in the RR database, there are numerous simulcast analog emergency services paging systems in place in this country, and all of them suffer from the same malady: multiple transmitters on the same paging frequency transmitting the same intelligence simultaneously.
I live in a county with a metro fire system that has UHF analog simulcast paging. It is not multicast on different frequencies from multiple sites, it is simulcast on the same UHF frequency from multiple sites, and even with the transmitter synchronization equipment in place and operating, it still creates a problem because of multipath issues.
You may be able to synchronize the transmitters to near perfection frequency-wise and modulation-wise, but with multiple sites transmitting on the same frequency, there is absolutely no way to fully compensate for multipath distortion and audio cancellation in any given location. The greater the number of transmitter sites involved and the closer the sites are located to each other, the greater the multipath audio distortion and audio cancellation problems.
Scanner receivers and pager receivers ain't all created equal, and most don't deal with multipath as well as some higher end mobile and portable radios will, but the bottom line is that regardless of your receiver's ability to deal with multipath, you will never be at a point that is equidistant from each of the sites where you could theoretically have synchronized signal arrival times. The reality is that since you cannot be at a perfect location, and if your receiver is able to copy more than one site at a given location with good signal levels, the audio is still going to be distorted for no other reason than the difference in arrival times of the signals at the antenna.
It ain't a perfect world out there.