I think followers can learn a lot faster because they're exposed to new moves all the time from leaders.

For leaders to build up a good vocabulary of moves requires a lot more than weekly practice though.

It depends (also I switch roles but primarily lead), vocabulary takes time, but you can have really, really good dances with limited vocabulary and good fundamentals, and often people focus on moves over fundamentals.

And fundamentals as a lead can be learned by dancing with intention.

It's too bad most people who try partner dancing don't stick it out long enough to break through the awkward stage to where it gets to be a lot of fun.

I think that's true for most hobbies, though. It's easy to bounce off anything that takes a bit of skill, because it can be a fairly large time commitment for an unknown payoff.

I've done lots of activies, including sports and dance, and some activities simply have a higher barrier than others.

Partner dancing - at least leading - is definitely on the higher side :-)

There are several factors. Leaders must endure months where they can do little or nothing, and they have to do it among people who always look great - if they social dance; if they don't, their learning time increases.

Then there's a lot of pressure of performing with and for somebody who's usually of the opposite sex (this applies also to follows).

It takes a lot (internally) before feeling comfortable enough to "simply enjoy".

Playing an instrument or practicing an individual sport doesn't have such pressures.

The dance coach I knew refused to video his students until they had reached a certain level of competence, because if it was too soon they'd be horrified at how they looked dancing and would quit.

Video is a brutal but effective teacher for those who are not easily discouraged.

Swing/lindy, west coast swing, waltz maybe. But it takes at least a year to become a good salsa dancer and Argentine tango even longer. The difference in these dances is the level of coupling (no pun intended) between the lead and follower. In Argentine tango both dancers meld into one moving unit and the brain has to learn how to do that.

It's unclear what the parent intends with "competent", and also not clear what "weekly" means (once a week? three times? daily?).

I've been an amateur dancer for years, and definitely, for what I personally intend for "competent", it takes 2/3 years at least, with multiple times per week of practice, a few workshops every year etc.etc.

There's certainly some people who dance pretty much daily and gets good in less than an year, some people with background in physical activities (sports or arts) who also get good quickly... but they're exceptions.

I assume by competent he means knowing the steps, how to lead or follow, and other basics. Kind of like how you can learn how to move the pieces in chess and learn basic strategy in a few months. You can get good enough to be better than 95+% of the population. You may set the bar for "competence" higher, but it's not a facially crazy assertion. That said my dance knowledge ends with a box step and I would definitely not call myself competent.

It depends on what you consider good, but generally it is possible to become a a proficient enough salsa dancer in maybe 2 or 3 month, if you are keen and work on it. Importantly, many (most) salsa courses focus too much on moves and not enough on musicality and the basics (also due to student demand). I would argue you can have great fun with the basic food work and 2-3 moves, and I know that most followers really enjoy the dance even if the vocabulary is limited, as long as there is rhythm. This applies to Salsa in general, but LA/linear is more focused on moves and Cuban more on musicality I would say.