The issue in 2008 was that the banks were doing a domino effect on each other. We don't see any such signs of that with Silicon Valley bank, and SIVB is smaller than Bear Sterns (and other banks) from 2007 crisis.
The issue in 2008 is rather that institutional investors (mostly money market funds) ceased to lend to banks, or only overnight. I am not saying that the banking system is as fragile as in 2008, it is clearly not. But it only takes a panic to cause another post-Lehman contagion across the financial system.
In this case, a number of banks are holding a lot of long-term debt as "hold til maturity", so they're not recognizing on their books that it has lost value due to rising interest rates.
Yet. They were pretty important to the startup ecosystem, and the rise in fear could imperil some of the banks that were sick already
https://en.wikipedia.org/wiki/Collateralized_debt_obligation
The standardized, so-called "agency" MBS on the SVB books really isn't anything like that CDO plague. In 2008, people were losing faith in the ability to even assign valuations to CDOs; SVB's problem with their MBS portfolio is that the current market valuation is obviously not what they needed it to be just now.
SVB is a relatively meaningless bank that can go under with very few knock on effects to the banking system.
Lehman was atop 4 or 5 player in the financial space when it went under and. A major pillar that propped up the system.
The two are so completely different in their importance.
Asset size does very little to show this though so I understand why at a first order look one might get the idea that they are comparable.