Oculus

Valve's goal isn't to sell a lot of headsets, but to show what's possible with high quality VR and encourage more VR games and headsets. Valve's ultimate goal here is to sell more VR games.

Oculus wants to sell a lot of headsets so they can push some kind of SM interaction and profit from having lots of ads. The priority there is adoption, not quality or compatibility.

Steam Controller was poorly made

No, it was well made, it just wasn't popular. And again, it wasn't their goal to sell a ton of them.

The goal was to design a flexible controller to build out their controller API and give an option for a decent desktop mouse replacement for a PC "console" format (i.e. Steam Machine). I think they succeeded at that, but the market wasn't interested, probably because Steam Machines didn't go anywhere. It was never intended to replace existing controllers, but to complement them.

Steam Deck is very expensive

It's $400, which is really competitive. Direct competitors like the AYANEO cost ~$1k twice as much, or even more. The Switch cost $300 at launch (OLED is $350, even today) and wasn't even competitive with current console hardware at launch, while the Steam Deck is competitive with both price and hardware.

And it's not cable tethered. I get a few hours of battery life as long as I'm not playing the most heavy games. Most of what I play are older AAA games and newer indie titles, and I get 3-5 hours of battery life, which is longer than my play sessions anyway. If I switch to a modern AAA titles, it's like 1-2 hours, which is still enough for most play sessions.

Their goal, again, isn't to sell a ton and corner the PC handheld market, it's to make PC handhelds popular so there's more demand, thus more competition, and thus more game sales. They also want to show what's possible with a Linux-based PC, so there's a credible alternative to Microsoft (and most games seem to be playable, check out ProtonDB for a larger picture than just Steam's official stamp; look at Proton DB medals, 77% are Gold or Platinum, which usually refers to "playable" and "verified" accordingly).

Steam's customer support

You claim it's worse, but you don't give examples of services that are better. Here are some examples of worse customer service:

• Nintendo estore - no returns
• PlayStation store - no returns if you have started to download it, unless it's faulty (e.g. Cyberpunk 2077), and even then you have 14 days
• Xbox - within 14 days and don't have "a significant amount of playtime"

And Steam's policy is 14 days and <2 hours playtime (so the same or better than above), yet there are countless examples of refunds being issued being both the time and playtime limit, provided you don't abuse it.

I'm not going to go through other examples because I believe I've proven my point, so now it's your turn: give specific examples of other stores having better customer service than Steam.