Being smaller doesn’t necessary needs to concern you in a street fight if you know how to use right techniques at the right time.
Let’s imagine that smaller guys are trying to outpunch big guys in a street fights. Their chances of winning a fight are significantly decreased. Taking your opponent down shouldn’t be a problem at all if you’re trained grappler against trained or untrained striker without any takedown defense training. Also we all know that smaller guys have lower base and their chances of staying on their feet are very good and if you combine it with their quickness and fast ability to clinch, grappling sports like BJJ, Wrestling, Sambo etc. are perfect for them.
What do you think? Is this the right way this small guy should fight? Are grappling Martial Arts perfect for smaller guys for 1 on 1 street fights?
Or check this video where difference between both guys is huge but the small guy still manage to double leg this big bully.
Or you can check how effective good takedown can be in a real situation. Judo guy was attacked by some hooligan but he managed to resolve the situation as fast as possible.