AirPrint-enabled Printers

Why is one printer model AirPrint-enabled and another model not?

Why? Simply because your printer predates AirPrint and was not made with AirPrint technology.

The MG5250 was made about 2010. Apple's list of compatible AirPrint printers has the MG series commencing with the MG5510 (about 2014?).

AirPrint was released by Apple in 2010. Printer manufacturers are generally slow to introduce new standards in their products, as can be seen in Canon's MG range where it took several years for them to catch up.

Hi,

You may want to check whether the Canon PRINT Inkjet/SELPHY app for iOS would support your printer.

https://apps.apple.com/us/app/canon-print-inkjet-selphy/id664425773

At least an MG5250 appears to have been supported:

https://www.canon-europe.com/support/consumer_products/products/fax__multifunctionals/inkjet/pixma_mg_series/pixma_mg5250.html?type=apps

If the above Canon app does not work with your printer model, there may be another solution. If you have access to a Mac computer running OS X 10.9 Mavericks or later, with working printer drivers for your MG5200 series model, a third-party Mac application called Printopia (https://www.decisivetactics.com/products/printopia/) could perhaps be of interest. The idea would be to use the (old) Mac as a print server, thus allowing printing from an iPhone/iPad.

Ask the manufacturer.

it has nothing to do with Apple.