Board Thread:Speculation, Theories, and Rumors/@comment-24989822-20150515102436/@comment-679780-20150522220852

The RPGs arn't considered canon to the Super Mario series and even if they were, prooves MArio doesn't not always possess the ability or else in future games would not be reliant on Power Ups.

And if Sonic wants to counter Mario's fire powers, he just needs a Fire Shield which makes those fireballs "poof". It also grants Sonic a burning dash like ability so he'll have more of an advantage in speed over Mario.