The developer team for Valheim is pretty small like perhaps 6 or 7 people and I think they hired like 2 more developers awhile after Early Access release. Even if you throw a ton of money at a small indie team they can only do so much when it comes to developing the game.

While we've had the Hearth and Home update that was on the road map, ice caves, additions to the swamp biome and plains biome - I imagine releasing a whole new biome would take quite a lot more time to finalize before being let out to the public or in some sort of beta form.

New terrain systems, environment pieces, enemies which would mean modeling, animation, texturing, programming, balancing, etc... and then you'd have all the new items associate with a new biome when it comes to weapon progression, building materials, food materials, trophies and whatever else.

Part of the risk in supporting an early access game is that you are paying for an unfinished product without knowledge as to when or even if it will be fully completed. In a way it's a gamble that one should only make if they wish to support the game and it's developers - otherwise just wish list the game and wait for a full release and reviews to see if you want to purchase said game.