I think it depends on what one defines wealth as.
It indeed depends, there are many mages who have commercialized magic, such as divinators on TV doing it for money, you can also find many commercial websites which exist primarily to make money out of magic by selling various occult related stuff.
I would define wealth as a treasure trove of knowledge.
Recently I've read in one book which says "the end of learning is learning the truth", but who will say "I've learned the truth", It's like one is trying to say to be all knowable, which is absurd, there is also another saying which goes "there are as many truths as there are people", thus if one says "I know the truth" it's thus very likely nobody is going to believe them.
Therefore 'true' wealth I think is the knowledge itself, the more a mage knows more wealthy they are (spiritually), and inherently more powerful.
Take a real life example, since ever there is new knowledge coming in forms of technologies, those who invented those technologies in almost all cases become very rich either by selling their patents or by commercializing their knowledge ex. by producing stuff based on new tech.
In any case however they do not reveal their knowledge to make sure others don't make money out of their effort.
In the end what brings them more money is knowledge and ability to come out with new ideas, money however is expendable.
Know that those books which layout spells to bring you wealth and buried gold were mostly written in renaissance era, and these books actually ruin magic, these books claiming to bring you wealth, obviously because nobody ever found buried gold with the help of such books.
And the reason for existence of such books is money, these books were so to attract buyers.
Red Dragon is one example of such book, I personally don't consider it to be a book about magic at all because it's a pure commercial product, made not with magic in mind, there might be some insights but the addition of buried gold ruins entire book.
There are many books about magic which are about magic rather than wealth, so if one seeks to learn and practice magic I would say avoid books about magical wealth and seek books about magic, books with spiritual value.
Of course every book is written to be sold but I'm not saying that these are thus fake, rather fake are those which offer real life wealth.
That is, knowledge about magic which is about real life wealth instead of spiritual wealth is not knowledge about magic.
And who is the Lord of Wealth?
I would say the one who possess knowledge (and is able to distinguish texts about magic from texts with commercial nature).
Know also one historical fact, which is that since ancient times mages, priests, healers etc. made their living from donations of those seeking help.
It was customary for ex. to not come before man of God or a mage etc. empty handed, this is a huge difference from commercializing knowledge by selling stuff for fixed price.
Can you imagine a cashier in the entrance of the church with a cash machine printing bills and collecting fixed amount of money?
I'm sure churches would soon be laughed upon and nobody would enter except to laugh even more, that would be pure commercialization without any spiritual value.
There would be a lot of suspicion about spiritual truth-ness and purpose.
Magic being of spiritual value and purpose, likewise, if commercialized or purely about wealth cannot be considered to bring any spiritual value or wealth or power, it rather brings only suspicion which ruins it.