But don't fall into the trap of thinking what commercial breweries do is what homebrewers should also do.
It can be a trap, but I'm not going to say it's always a trap. What commercial brewers do, homebrewers _can_ do. With limitations. Sometimes the scale means it's not possible, or that it needs to be heavily modified. Often it's no longer worth it. But there are good ideas that you can learn from. You can reuse yeast for a while and you'll probably get better results than from first generation yeast that was grown in lab wort. When you get to the point that you have to start acid washing it, it's really not worth it when you can start over for $8.
There is a possibility of genetic drift, also, but I didn't encounter that in the lager serially re-pitching (that I could tell from taste or aroma). Perhaps I just got lucky. Also, I was usually racking from primary, harvesting and re-pitching on the same day, so I brewed many similar styles in succession with large, healthy re-pitches. Again, keeping yeast in a short dormancy helps things out. This is just one person's experience and YMMV, as always.
I would typically harvest up thru the 8th generation. We always did a single primary ferment, then would collect the yeast from the bottom of the fermenter and store it in a glass jug under sterile wort, typically at 35-36 degrees F. Time in storage was 2 to 4 weeks.
With each new brew, the yeast would literally explode from the flask after being "woke up", sometimes climbing outside of the container and going onto the countertop.
It not only worked great with zero lag time, it also tasted better and saved us some $$$.