I have also become a less-cleaning guy, but during "shake out"* I clean/lube, fire a bit, clean/lube, fire more, clean/lube then (assuming no problems) put into service.
Cleaning is important first because rarely** is all machining residue removed (machine oils, degreasers, metal waste) from the factory and you want to remove all that, replace with nicely-lubed surfaces. For anything, not just guns***. Cleaning mid stream, during mechanical "shake out," things are wearing into place. There are going to be more and new waste products, metal flakes, etc. We clean that off to avoid excess wear.
A also, it is critical to pull it apart to inspect stuff. Things that are going to break soon will break and you want to see them, or the precursors (gouges, etc.). Look for damage, cracks, and too much metal scraped off or marking other components. Functional mechanical items do not just operate, but exhibit all signs of continued operation on inspection.
I agree c. 200 rounds is all you need to assure good operation, AND that I ignore all stoppages in the first 50 or so.
Now... if I get stoppages in or shortly past the first 100, it's not declared reliable until 500 rounds in. It happens. My example was a Century C93 which didn't do 2 rounds in a row for the first mag, but sloooowly got reliable, and I haven't had a single stoppage with any ammo under any conditions since it passed about 175 rounds. But, I didn't trust it until I got to 500. It was Century-fit, so needed the wear-in period to work.
Stoppages past 500, and we're not going to get fixed easily. Sell it (or repair, etc).
Cracks, gouges, etc. at ANY time, mean return for warranty work or so on as applicable.
* It is still mechanical
break in, a term used in every other mechanically-inclined industry, but that seems to confuse everyone when it's guns.
** Rumor aside that they are perfect, even Glock says it's
okay-to-preferable to remove the copper "grease" and do a clean/relube for break in. I have also seen plenty of metal flakes come off them. They are still machines.
*** From night vision to the kid's humidifier, once I unbox an item, I first remove all the normal-operation bits and lube them up properly. Battery screw on caps get dielectric grease, o-rings get whatever lube best applies, plastic-on-plastic get silicone, and so forth. Everything gets at least a basic shaking/brushing out, and a lot of times chunks of material and screws fall out of things.