According to McKinsey, there are two! One growing and one stagnating:
The productivity of small firms is falling, while that of large firms is rising. In itself this would not necessarily be terrible, but the size of the large firm sector is not growing much, so around 40% of workers are “stuck” in the falling productivity sector.
Maybe this is just Baumol, and the small firms are all string quartets, but maybe this is a real problem for the country.
Of course, this is just accounting so there’s no guarantee that if the share of workers in the more productive sector doubled, that productivity in that sector would continue to be high. That is to say, there may be a “supply of qualified workers” constraint operating in the country.
How many Mexicos do you think there are?