I hope this isn't true!, in the sense that I hope that gaming groups are capable of making of the game what they want. I have run RM games, for instance, with very different distributions of wealth between them, and also within a campaign with different PCs having quite different levels of wealth.Putting expected wealth and the like in previous editions led to a tremendous sense of entitlement on the part of certain players, and without those "expectations" in the books, groups are far more likely to tailor their campaigns to their individual tastes.
In 1st ed AD&D, the wealth requirement is somewhat dictated by the XP rules. I can't really comment on 2nd or 3rd ed, but in 4e wealth is very flexible provided the "big 3" enhancement bonuses are covered (via loot drops, spontaneous item upgrades (which is what I use in my game) or inherent bonuses). I'm not surprised that 5e aims to be at least this flexible - though it does have creatures with resistance to normal weapons, which suggests that magic weapons of some sort will probably be a requirement above low levels in most campaigns.
I think inflation is a pretty big issue in mediaeval economies, insn't it (though not one that D&D models).I like the notion that WBL doesn't grow as it did in previous editions for new characters. Even were a character to be introduced at a higher level, one presumes that they'd be adventuring less, if at all (else they would already be a PC), so they'd have less of a steady surplus of gold to enter into the economy (while the game's economics aren't true to medieval economics by any means, it is more realistic that Total Wealth in a population doesn't grow within a bullion-standard the way it does in a fiat-standard unless new bullion (like hoards of dragon treasure!) is introduced – it's actually a pretty decent concept of mercantile economics after a fashion!