I guess it always depends on why you think you need protein supplements, and yes, most people should be able to get what they need from a healthy diet.
If you were vegetarian, or had particulalr allergies then perhaps you need a protein supplement.

My partner is a top cyclist in our club, and is hoping to defend his national medal in his vet class (45-50years) this year. He bikes about 400-500km a week, though with Nationals only about 2 1/2 weeks away he is reducing that to about 300kms.

Thats alot of hours on the bike - but he has no protein supplement. He eats loads of fruit (fresh and dried), nuts and has beef or nutmeat most days. He eats no pasta or bread, having rice and sometimes crackers. He eats a little yoghurt or cheese sometimes, and has a low fat/low sugar milk on muesli several times a day.

Pre-race (his races are between 60-100km long) nutrition is usually a tin of pears, or a tin of creamed rice.

The only supplements he has are magnesium before and after longer or intense rides, and glucosimine when his knees play up.

Do consider why you need to buy supplements - I think alot of people are fooled by the marketing, and spend unnecessary dollars.