Lazarus already comes with tonnes of components (over 200) and lots of libraries but yes, it is still possible that you want to access some functionality which is not provided natively by the built-in components. But then, you may not.
True. Lazarus/Delphi are the "APEX predators" for UI building. Their only caveat is their lack of resources (Lazarus) and weird costly licensing (Delphi).
Yes, the Delphi licensing cost is horrible. However, if you are using Lazarus you don't need to use Delphi at all.
The lack of sufficient developers who are familiar with Lazarus/Freepascal is a problem though. But again, this is a chicken and egg type of issue.
Getting up to speed in Lazarus does not take very long though because the IDE itself guides a person through in the components and you can clearly see the properties and components they have etc.
Compared to the challenge of wrangling many of these cross-platform frameworks to develop a desktop, it is a piece of cake in Lazarus.
Sadly, what keeps Lazarus back is the fact that most people aren't even aware that it exists and a perceived notion that it is not a cool/capable framework.
I would actually say that it is perhaps the fastest in the list.