In the case of meraki this was NOT always the case. Can't speak for other cisco gear. We used to sell meraki like hotcakes back before the cisco acquisition.

The old, pre-cisco behavior for an expire licence:  

• no more software updates pushed to devices from the cloud
• no access to advanced features on cloud dashboard
• SSIDs and very basic configs remain functional and continue serving clients, ability to make minor changes like SSID passwords/configs remains.

post-cisco (not overnight but after a while):  

• all meraki devices on your account stop serving clients upon the expiration of any one device's licence and subsequent expiration of a grace period basically threatening you via email to cut off your network.

Suffice to say we do not sell meraki anymore. The old model was perfectly acceptable. You want to purchase an AP to serve wifi to your clients and nothing more? Then just use it even post-expiration if you didn't find the cloud services were worth it.

The new model is unacceptable and we've even had to defend ourselves legally for selling devices pre-cisco that then went on to stop functioning post-cisco.