Right, but your 99% of people ignore magic LIKE it does not exist. They "know" it exists, but then just live there mundane life. Magic could cook my food in minutes....but, nope I'll take a couple hours to cut down a tree into logs and then carry them back to my house and then start a fire with two stones and cook some food over the next hour.To be clear, for myself anyway, when I say 1 in 100 creatures can "do magic" doesn't mean in ANY SENSE that the other 99% think magic does not exist, etc.; just that only don't know how to do it. Most people understand that there is electricity but the vast majority don't know how it works or understands really what it is, let alone know how to produce it!
So, in my games all (or 99.9999% or so LOL) know magic exists / believe in it/ etc., but the vast majority can't do it.
The person does not need to "create" magic, just use it. Someone who uses electricity in a kitchen, does not have to build a generator substation with transmission towers. They just get a socket installed and plug stuff in.
The default generic setting of D&D in adventures always have tons of spellcasters as needed. When that evil group has like 20 spellcasters, well, gosh that should be like ALL the spellcasters on the whole continent , right? Oh, wait, but the city guard has like 20 spellcasters, oh and the mages guild has like well more then like five members. And on and on.