Can a startup succeed solely based on execution?

And typically the ones that succeed execute one thing much better than their peers: distribution.

Whatever you do, someone else will be able to do it faster and cheaper.

Also, read up on the "Red ocean" vs "Blue ocean" theories about competition.

Yes, you can compete in the cut-throat red ocean, where all other competitors try to survive by offering roughly the same product or service. Look at basically every AliExpress shop.

But it will only get you so far. Will they survive in the long run? To really succeed, you have to offer something unique. Production efficiency is of course on everyones radar. No company ever said "we dont care about how much it cost to produce our product/service".

Google wasn't unique when they started. There were several other search engines out there, Alta Vista being the largest one. Both offered their services for free - so how can you possibly compete on price in the Red Ocean against all other search engine? No matter how efficient the execution was, they had to attract people. Because that was what they were selling. People are the raw material. So, Google offered a different experience than all other engines. That way, they eventually got more and better raw material (people) to sell.

Apple tried what everyone else did back in the early 2000s; Sell mobile phones. But they did not become the world's second largest handset maker by being the most efficient at developing or producing them. In fact, they deliberately sold their phones at a loss for the first years. They decided that they would provide a completely new experience, and that eventually people would be willing to pay a premium which turned out to be twice as much than an android phone with comparable hardware features and costs.

SpaceX, on the other hand, have gotten the world leader in rocket launcher thanks to outstanding execution ; instead of destroying every rocket once the payload has been deployed, they are reusing the rockets, thus keeping the cost per launch much lower. Noone else have yet been near their reusability and cost per launch - because its litterarily rocket science, not because the competitors are less efficient in their execution.

Thomann and Behringer are some of the world's largest companies in the music instrument business. They have perfected execution to such degree that it is hard to find cheaper alternatives that are comparable even on AliExpress!

Ingvar Kamprad started his first company by buying pens in big-pack, selling them piecewize at a large markup. Later the company decided - similar to Behringer - to copy the design of well-known furnitures, but optimize the logistics, eventually also optimizing the manufacturing process. IKEA is now the world's most famous furniture company. But, even they can't sell the cheapest bookshelf anymore.

A successful business is mainly about managing resources and people. The idea is secondary.

I would bet on a successful team over an idea any time.