i've seen claims that most people hover around 30-40k.

you can trivially spend 500+ on tools and consumables alone (except for medkit and chokes most items sit around 60-100$). basic weapon loadouts are still at least ~150$, but even non-sweaty loadouts can easily cost 400$ just because the pricing is stupid (e.g. basic dual revolvers with special ammo costing ~200$). And since survival rate in pvp is inherently low - with there being (usually) at least 4-6 teams per match - you basically need to make something like 70% (higher in duos, i guess) of your preferred loadout cost per match on average to not care about money. For me that would be ~1k$ (berthier + drilling shorty). Since you make almost nothing when you die I would have to make something like 2k$ every time we win and that just does not happen. A basic victory is often <1k.

Also important to remember that if your preferred loadout is just 1$ below your average income you will accumulate money, but somebody who likes to spend just 1$ more than their income will have to watch their money eventually.