That's a pretty arrogant response, IMO. A computer may be important to someone, but giving his or her children an education may be important too, or getting medical treatment, or buying healthy food, etc. etc. To say that "even lower to middle class people can find room in their budgets for" a Retina MacBook Pro is very condescending.
I love Apple products, but they are expensive and far more accessible to the wealthy than less fortunate people. They're worth the money, but in a perfect world they would be cheaper so more people could enjoy them.
If you spend 8 hours a day in front of the computer (1/3 of your life) you can afford to pay the money over a large period of time.
Like I pointed out, you'd need to raise an extra $100 a month to get it. That is a trivial amount for anyone who is able-bodied and of sound mind living in one of the wealthiest countries in the world (I grant an exception to this to anyone who is living in a 3rd world or otherwise poor country where there isn't much opportunity and average incomes are much lower).
Like I said, You can convince 4-5 neighbors on your block to pay you $20 to mow their lawns and you're there. Then when winter comes, shovel some snow. Its a few hours of extra work on the weekends but it makes your dream of having a great device come true. You can decide if its worth it.
It really depends on your priorities. The same people who say they cannot come up with $100 a month for something they will use 8 hours a day for the next few years (or more) will also not blink twice about paying $100 a month for Cable TV they never watch.
The same people who say they cannot come up with any money will also ignore the piles of crap they have in their garages or attics that they can sell (including their existing computers) which can also offset the upfront cost of buying a new computer.
I am not suggesting that someone with deep struggles can easily buy this, but upper-lower to middle class folks can do so. If you are single and make an income of $15 an hour or more (the US average is $23/hour according to the labor department), or if you got two people working in a household, you can buy it without having to win the lottery.
And if you are stuck in a crappy job, than rather than hoping to win the lottery go improve your skills a little bit and get more money or a better job. The economy won't be down forever, but even with this economy theres plenty of opportunities to make a few extra bucks if you're willing to work and you have decent skills.
People just have to take initiative. Its been shown time and time again that if you take initiative, good things happen. If you sit around moping about your situation feeling like the only way you can earn $2,000 is by winning the lottery, you're of a losing mindset.