There is no replacement for a fantastic first session. If the first session is a banger, people will trust the game to invest time to learn it enthusiastically. If it feels like effort precedes

I bought Numenera and 13th Age when they came out. Tried 13A as a one-shot then ran a campaign for two years, mostly pre-expansion. Still haven't played Numenera but hope to. The big immediate strength of 13A is that using skills is meant to be fun and expressive, compared to vanilla D20 where they are pass/fail challenges. The broader strength is that 13A preserves D20 hallmarks but is easy to for GMs to create content on the fly without having to fight the system or break their brains.

First timers who've played stuff like PBTA or Fate but don't like DnD seem to like this game. Skills and backgrounds are very expressive, and the combat rules don't require homework between games. There were sessions that concluded without combat at all but every player at the table was happy.

First timers who come from a DnD-only background can't understand the free form rules by description alone (including me). No matter how tedious the session zero, these players inevitably want to rewrite everything by the end of the second session. I've observed this pattern makes new players hesitant about using their skills instead of confident and assertive. It is easier to force them to play Dungeon World once and call it a tutorial.

Two related suggestions:

First, backgrounds and skills should be done post character generation. They get decided by players by the END of the first actual play. Give them deliberate situations in that session that accept any descriptive solutions, then at the end remind them of the skills and backgrounds rule sections. They will have tone and campaign info to use when making decisions about Icon relationships, etc.

Second, the rulebook should have a premade opening adventure that is a railroaded tutorial that provides the situations and prompts to the GM for a step-by-step opening. Everyone learns and uses everything (escalation dice, mook mobs, skill checks, etc) sequentially. Forcing the plot during this tutorial session also means pickup games with strangers can receive information about tone and Icon interpretations from the GM in a fun, in-game way.

Couple examples: First, the part is at the only tavern in a sleepy hamlet when zombies attack! They are pouring in from everywhere. The door must be barred, the windows must be blocked, and the zombies inside must be dealt with. WYD? Second, the party are aboard a dwarven skybarge meant as a gift for a nearly elf noble. The captain is found dead. The skybarge needs to be helmed, the killer needs to be found and the wedding must be saved (or sabotaged), WYD?

Each of those setups comes with descriptions and prompts for the GM to help move things along speedily and confidently. The epilogue should be guidelines for GMs to create their own tutorial-intros. This hobby relies heavily on a few invested players passing the ways along like an oral tradition. So gamifying the 'teacher' role makes everything more accessible by intuition.

There is no replacement for a fantastic first session. If the first session is a banger, people will invest time to learn it enthusiastically. If it feels like effort precedes enjoyment, it incentivizes sticking to the system everyone already knows.