If IP disputes stop you using something when society as a whole really needs it, it doesn't really matter if the existence of IP was an efficient way of motivating the creators of that thing, as it is still effectively useless.
Patent law already covers this case. TRIPS Agreement, article 31b allows "society as a whole" to use a patent without even contacting the patent holder "in the case of a national emergency or other circumstances of extreme urgency or in cases of public non-commercial use."
Now try replacing IP with personal property.
Personal property is subject to compulsory purchase all the time for municipal infrastructure and in times of emergency is subject to state requisition without compensation.