Well what can I say, here is a quote from an offical WOTC 5E adventure (BG DIA):
"Coin trumps morals in Baldur’s Gate, with profit being the ultimate good. As a result, nearly anything can be bought and sold in the city’s shops"
In any case I've played games where there was tons of money and tons of magic available and games where there was little. The problem is not buying magic items, the problem is powerful items, like Rings of Resistance or Viscous Weapons not requiring attunement.
I am playing a game right now with currently 16th level characters who have tons of gold, and magic items up to Very Rare for purchase in multiple Greyhawk cities, but the lack of attunement slots (and the houserule on 2 rings) severely limits what they can buy and use effectively.
My character in that campaign is a Elemntal Evil Warlock 6/Eldritch Knight 10 and she dual wields a +2 Shillelagh Club and +2 Pact Scimitar as weapons. She could have got a Flame Tongue or sword of sharpness or Thunderous Club or a host of other things that would do more damage, but those things are attunement and she has a Wand of Fear, Ring of Spell Storing and Wand of Fireballs already.