I recently ran across a Youtube video where someone was complaining about the long effort to get a Griffon in Guild Wars 2. Griffon is the first flying mount in GW2. I won’t link the video as I’m sure he’s moved on and is now struggling with the many times longer process to get a Skyscale mount. I starting working on getting Skyscale in November 2020 and finally got it in January 2021.
As we know, different MMOs have different requirements for the use of Mounts. Let’s review:

World of Warcraft
Work hard on each character to get your ability to use mounts to ride, swim and fly. And the “License” to do each of these costs a lot of gold. So the gate for each Alt is your level and Gold to buy the license. Each mount you collect however is added to your Mount collection and can be used by all your alts, subject to faction and ground vs flight restrictions. Store mounts add nothing beyond new “Skins” to your mounts. Aquatic mounts are different mounts. Later expansions added long achievements to fly in areas. Warlords of Draenor was the most punishing.

Final Fantasy XIV
Some mounts are very hard to get, and some are very easy. You need to work for each and every mount on each and every Alt and for Flight in each and every area – although at Level 50 [ARR MSQ complete] you can fly in all ARR zones. Some Store mounts are “Account Wide” which means you can use these “Skins” subject to your ability to ride / fly your Chocobo in those zones. All mounts can be ridden or flown or swim wherever your character can ride or fly or swim. The header picture for this post is an 8 person Store mount recently released in FFXIV. Unlocking flight in new expansions – Heavensward, Stormblood, Shadowbringers – is quite easy. Talk to some items that tend to be on top of easy to reach places to Attune to the Winds in a zone and do some easy side quests. Nothing too hard in addition to completing the Main Scenario Quests for a zone. The most difficult mount to get may be the Amaro that I have almost acquired. Get all 17 War and Magic jobs to level 80. And that is Per Alt if you want it on all your characters. There are many mounts that require completing high level raids or other difficult activities.

Guild Wars 2
Mounts are unlocked by a level 80 character in the Path of Fire expansion and mount features such as swimming are then unlocked with various Achievements and Masteries. These accomplishments are Account wide so any part of these can be completed on Alts. Once acquired, mounts are account wide and low level Alts can ride / fly / swim in all zones. Even low level characters from the beginning in starter zones.
There is a “Warclaw” mount that can be gotten easily even by level 31 characters even if you don’t play much PvP by doing a little WvW [World vs World] play. Warclaw is a riding mount works in PvE zones as well as WvW. But the quickest way to get a mount might be to get a “Carry” for the path of fire story beginning from a friend or Guild Mate.

Rift / Black Desert / Neverwinter / AION etc.
Other games tend to follow a pattern of giving you a mount very early in a quest chain and each Alt must complete this same quest chain to use and have mounts. Sometimes “Gift” or “Store” mounts are account wide.
As an example, in Tera, characters acquire riding mounts at level 11 but don’t fly until level 60. Tera waited a long time to add flying mounts. Different mounts have different “skills”. Most ride and some fly. Flying is available in low level zones. Way back in 2015 I was getting the Sparky mount on new Alts by visiting about a dozen areas all around the world. I was able to get Sparky by carefully visiting the high level areas without causing combat with high level Mobs. Sparky is quite a bit faster than the horses you get early in the game.
Rift does not provide flying mounts. But riding mounts are available as soon as you leave the starting zone. The horned lion above is an early mount in the Rift game. Check my review after playing for a while.
May You Walk in the Light of the Crystal or May the Six Bless You.
:ww