I knew there would be a polar opposite reaction to my post, so here is my real world reply.
A few years ago I built up a Ford 289 K code engine for my '65 Mustang Fastback. This is a very special and rare engine so I was keen to get it right, however after a few miles of driving in 'running in mode' I was starting to explore the potential - and it was disappointing.
So I did a compression test and the results were worryingly low.
I previously had read a comprehensive guide from an American auto engineer on the subject of breaking in new engines and he advocated making the engine work hard from the off approach, providing all temps and pressures were good, to ensure the rings bedded and the bores did not glaze, it did make sense to me.
So the Mustang was treated to a good spirited talking to, not to max rpm, but to the rpm that max torque is produced, ie 4500 or whatever, quite a few times and run down by changing down to load the rings on over run.
A return the garage and another compression check revealed an increase of an average of 30 psi per cylinder. I was lucky, I had not glazed the bores.
A friend of mine built a Cobra replica with a Ford 302 and ran that in by driving like a Vicar, it smoked and burnt oil terribly, and it ruined his enjoyment of the car.
Now at work ( I build Aston DBR1 recreations ) every new build gets the 'treatment' right from the off and so far so good, no problems with failures and all engines are smoke free.
The Elan I have owned since a boy was run in by not exceeding 3000 rpm and only light throttle openings, I wish I had ripped that up higher and loaded the rings, I bet it would be a nicer engine now.
Anyway, just my 2p, each to their own.