A top notch machine is only like 50% faster for 2-3 times the price. You don't need it. You can just get a console or a budget PC for $600. If you are crazy you can spend $300 on a PC and only play dota 2 and 2D games like Terraria, Don't Starve Together or Rimworld.

Also, what makes you think that 5/6 of the world has fast internet? I have good internet but if you asked me 3 years ago I would have said no.