Lawmakers and law enforcement have challenged the move from several carmakers to drop AM radio in new vehicles, citing its vital role during times of emergency.
www.foxnews.com
^^^
...pointing to the role AM radio played during Superstorm Sandy in 2012
This article cites people who are clearly uninformed on the subject.
AM Radio was nearly totally off the air in NYC and environs during Sandy, and so it could not have been vital to emergency responders.
Essentially all the stations which transmit from the Meadowlands in north Jersey were knocked off the air. To wit: 1010 WINS, WMCA 570, WNYC-AM 820, WNYM 970, WLIB 1190, and several ethnic stations were all off the air during the storm. WOR was on the air but lost its studio and had to simulcast TV audio. Newsradio WCBS and WFAN were off the air for several hours even though they don't broadcast from the Meadowlands.
The FMs at Empire State remained on the air, although some had trouble at their studio or getting audio to Empire. At some point, CBS Radio began to air 1010 WINS on 92.3, and Newsradio WCBS on WCBS-FM.
Contemporary coverage from Scott Fybush's NE Radio Watch lists lots of other call signs with storm damage
Basically, the AM radio system is so simple (doesn't need a large number of terrestrial towers or expensive Satellites), it seems like, even if an AM radio raises the cost of a vehicle a few $, it's worth it.
On the contrary: in your plan, losing 750 WSB would remove EAS service from much of the Southeast, whereas losing one cell tower might remove Wireless Emergency Alert service from a few square miles.
The cell network has a certain amount of redundancy built in. Just because the one tower nearest you is damaged from an earthquake, hurricane, flood or tornado doesn't mean you won't be able to get limited service from the next furthest tower.