They might be able to afford it, but money is money. The question would be whether the cost of keeping the patent outweighs its potential profits.
A possible solution is to require the patent filers to declare the price at which they are willing to permanently release the invention into the public domain in exchange for a one time payment. Then if someone is sued for IP violation the defendant can crowd-source the inventor's fee and pay it through the patent office to have the the patent destroyed immediately without hiring lawyers or halt production.
The IP registrar could then levy a quarterly maintenance tax on the quit price filed by the IP holder to prevent the inventor's fee from being set infinitely high.