A few points to consider: We have to put instruments into the context of all consumer goods inflating in price. If we use 1960s Fender as a standard-bearer (seeing how the majority of musicians were playing them at the time): those basses when adjusted for inflation would be $2k-3k today. But back in those days, budget/import basses were often pretty poor quality, and not often considered "pro" instruments. So consider that everyone you saw playing a "pro" bass (Fender / Gibson / Rickenbacker) had spent well above what we think of as "budget instrument" prices for new instruments. But also, many probably players didn't have large collections (I say probably, because there were guys like John Entwistle to consider)
Today, budget/import basses are substantially better than they were decades ago, and many players use them as "pro" basses. We can acquire collections of many basses and have an array of great options on-hand, all without breaking the bank. But that often comes at the cost of cheap overseas labor with questionable wages and working conditions for the people building them. This isn't news for most of us, and it's something I digest with mixed emotions and moral conflict.
Knowing that, it makes $2k-$3k and above seem appropriate for an instrument made domestically, by crafters who are building high-quality professional tools and (hopefully) making justifiable living wages. For my own anecdotal contribution, my main bass is a Serek MW2 5-string, made to order at about $3.5k. It does what I need for 90% of my gigs and leaves me wanting little more, but for a few other mellower options. I'm an advocate for quality over quantity; while it's still very important to shop around and try different things, I think in many cases we still get what we pay for.