The reason you need conventional oil to "break in" your engine before running synthetic is the exact reason why running conventional oil all the time is probably not in your best interest. It ALLOWS wear, meaning it's not providing full friction protection and is allowing small amounts of material to be worn away in your engine! good synthetic oils are so good that they won't allow an engine to wear in as needed to properly seat the rings, which will over time cause them to blow by causing lower power output and oil consumption.
No one is saying to run longer than spec on the oil changes on small engines, if they did they are wrong. I change mine every 100 hours, using amsoil air cooled formula oil. I've never seen the need to change oil every 50 hours in a machine that has a filter, even with conventional oil. I also change the filter with EVERY oil change, even though the engine mfg usually recommends changing the filter every other time. Which makes no sense to me...