You make a reasonably compelling argument but it still falls flat on the basis of what you choose to hold any given person responsible for.
You can't just arbitrarily draw a line in the sand and say 'these people lack self-disipline' therefore everything is their own fault...
Yes, I know people that spend all the money they have on alcohol, or drugs, or similar stuff, then beg for more.
You can't help some people by giving them money, in the end.
But success and failure aren't simple correlates with how hard you work.
Working harder won't make you more successful in and of itself.
Neither will being lazy guarantee being poor.
Sure, to a point, you can improve your own circumstances, but all it takes is one misfortune to put you into a practically unrecoverable position.
Being master of your own destiny has it's limits.
What's worse, the choice in attitude has negative consequences. I can, and do see people get mistreated simply because they are poor.
Why? Because people think it's their own fault.
It doesn't matter if it is or it isn't the person's own fault, but time and again i've seen the 'you are responsible for your own fate' line of reasoning used to be outright abusive to anyone who is poor, with no care or consideration given to why they are poor, but just the implicit assumption that they are the only ones responsible.
The flip side to this is of course letting people off from taking any kind of responsibility for their own actions, which is, ironically, also harmful. And in particular, it's actually harmful to the person themselves.
Then of course, as a European, the 'welfare trap' comes to mind.
This is the psychological trap that results from getting government handouts.
Some people use it to justify not giving people anything to begin with, but the real problem is that the system is rigged (as with your example of the handicapped) to be counter-productive.
If you can barely afford to eat, and are then obliged into a situation which actually worsens your financial situation, (it's not just that you don't gain from it, but you actually go backwards...) who in their right mind would actually do it?
It's like being asked to work more hours at your job, except the harder you work, the less you get. Not much incentive there.
Welfare systems are fine in principle, but why are so many of them rigged to actively discourage people to try and improve their circumstances?
There's a difference between being poor and being unable to go see a movie when you feel like it, and being poor and having to decide if you can actually afford to eat something today...
But basically, I very much doubt people have anywhere near as much control over their lives as you think they do.