Purchasing over-valued stocks in businesses that use their shares as currency is fought with risk and I would agree that most of the time this does not work in the long run. I think the primary danger of these roll-ups is the people element ie it gets really addictive to see those revenues, cash flows, and stock prices go up and to the right over time. Doing this as the only business strategy will most likely end in failure ie conglomerates in the 1960s (ITT, Litton), Mississippi Bubble, South Seas Bubble, etc.
Similarly, Cathie Woods' business of pumping world-changing tech companies based on a story, is also not investing but gambling/speculating. However, that said, I think we can learn something from everyone including her (ie she introduced me to the mental model of Wright's law which I later read in Bionomics - which was an interesting read btw).
But for the few truly good allocators out there, using their stock as an acquisition currency, is a lever that can be sometimes pulled or repetitively pulled in the right situation for the long-term. Other examples that come to mind (please correct me if I'm wrong about the details)
- Buffett issuing shares to purchase GenRe during the height of the dot.com mania
- Prem issuing shares to purchase undervalued insurance companies during the early 2000s
- Singleton during the 1960s using Teledyne shares to serially acquire companies (see link below)
The reason I started this thread was not promote buying over-valued growth stocks especially when the market feels toppy (and Buffett is a net seller, holding lots of cash), but better understand the rare situations when this is actually rational and why.
Just like buying low PE stocks without discrimination and concentrating them in your portfolio, isn't intelligent either. Eliminating ALL over-valued growth stocks without discrimination could result in a significant opportunity cost.
PS: found this case study about Teledyne that people might enjoy reading
Teledyne Technologies—A Conglomerate Phoenix That Rose from the Ashes with Henry Singleton’s Corporate DNA Intact