Nuix valuation from their competitor Cellebrite, page-5

lol Chad the answer is that its multiple causes:

The underlying 1st level causation that are independent of interest rates:
Are the Many Growth companies have tended to be in companies that are beneficiaries of the 'Internet of Things' Capital destruction of the 'old world' business models and being replaced by new world technology. Think traditional media companies vs carsales.com, realestate.com etc. Think Apple and Microsoft. Think banks vs new age payment systems: visa, paypal. These types of growth companies (unlike the dot.com boom) have had real and sustainable earnings growth.

The 2nd level causation that are dependent indirectly on interest rates:
The stalwart growers like CSL, who's valuation can be compared to the risk free rate (ie interest rates), as interest rates have declined the risk free rate of return has declined and the justified valuation stalwart growers has increased.

The 3rd level causation is the psychology of markets:
As growth companies share prices have increased those that buy the 'trend' jump on board. Trend followers are not interested in valuations they invest based on the trend, and the trend is up, so buy and buy more as the price goes up.

The 4th level causation is self reinforcement:
Those that have participated in the rally congratulate themselves and what ever their logic. Whether their logic was correct or not is irrelevant. They have been 'proven' correct by the continued increase in the share prices.

These factors intertwine and continue to reinforce each other, and what starts as logic ends up just being stock mania.

That is why I use absolute valuations, I don't want my investment returns beings determined in the long term by the opinions of others or the market as a collective whole. When I buy, I couldn't care if the market shut for the next 10 years, my decision to buy is based on part ownership of the underlying company and my expectations of its future returns: does the investment case stack?