The thing is that "normal" single skating should also be about more than just the bv of certain jumps. While I agree that it's cool to have more "accessible" options for athletes who did not start out extremely young, do not have a partner or do not excel in jumping, I fear that should those two disciplines continue to grow and become more popular more people will say "well, if you can't do a triple axel by 10, then go do synchro or solo dance".
They certainly wouldn't say that.
They might say "If you can't do a
double axel by 10..." but still it's up to the skater whether to pursue singles skating (with the understanding that they're unlikely to reach elite levels) or to switch to a different discipline that doesn't involve jumping.
Under current rules, double axels are not required until junior level for the short program. Junior men are required to do at least one triple in the short program; junior women are not.
So there's plenty of time for a skater to compete at what the ISU calls basic novice, intermediate novice, and advanced novice without a double axel or any triples, and at junior without triples (or without many if male).
Sure, they wouldn't be winning medals, or international assignments unless they're from a tiny federation, but skaters are able to keep competing singles with only double jumps until mid to late teens, when they would age out of the ISU age/level divisions that don't require harder jumps.
In the US, novice (=ISU advanced novice), junior, and senior divisions are considered skill levels, not age levels. There are no age restrictions domestically at those levels. I have, rarely, seen 20- and even 30-somethings competing in novice.
The US also has a separate competition track called Excel that uses strict limits on what jumps are allowed at each level. Double axels aren't even allowed in any Excel level until senior level. (There are no short programs and therefore no minimum requirements except having passed the test for that level, or one level below.) It's not intended to be an elite track and therefore will never lead the international competition.
So in the US there are plenty of options for skaters to compete as singles skaters with double jumps only at any age. If they want to jump and can't do double axels or triples even as older teenagers, and certainly as adults, they have several options.
If jumping is not important to them, they have different options.
If they want to compete
internationally and have the skating skills for that to be a reasonable goal but don't have harder jumps, then they might choose one of those other options, especially as solo dance grows as an international sport.
But if they're just in it for fun and personal challenge, they can continue as singles skaters if that's their preference.