Why does everyone think Sparta is stronger and powerful than Athens HELP PLEASE?

Answer 1

Sparta expanded its territory and turned the population into serfs, who supported the Spartan citizens, allowing them to devote themselves to military activities, and so field a fully-professional army.

Athens, like the other cities, depended on calling up its farmer and tradesmen citizens for war service as required for contingencies, and theoretically were not as well trained and experienced. Also, Athens concentrated on sea power, using its city walls to protect the city, and being able to harass enemies with sea raids. However its army usually gave a good account of itself when required. Sparta's weakness was in numbers.

While Athens could turn out 10,000 armoured warriors at Plataea in 479 BCE against the Persians, Sparta could muster only 5,000. And this got worse for Sparta as accumulating battle casualties over the next century so reduced its military manpower that it ceased to be able to compete and it slipped into obscurity.

Sparta in its heyday was able to multiply its power through the Peloponnesian League which it led, being able to turn out such allies as Corinth and Thebes. When these alliances broke up Sparta was isolated and in 370 BCE was defeated by Thebes and never regained prominence.