What do you mean might?

Is there a major RDBMS out there that struggles with 150MB of data?

Of course any major RDBMS would have no problem with the data. If the reports here are accurate, you could fit the last 5-20 years of all NOTAM messages into the RAM of a Raspberry Pi running SQLite.

But if that's enough, why hasn't the FAA solved the problem already?

And even a "major RDBMS" is vulnerable to stodgy management leaving design in a state where it's vulnerable to a single central point of failure, where "2 contractors who introduced data errors" (!) can bring it down.

Modern highly-distributed consensus systems are not vulnerable to that. Neither accident nor malice from 2 government contractors could prevent all authorized updates worldwide in a distributed consensus system like Ethereum.

DC & northern Virginia (or wherever the FAA's systems hosted) could even spontaneously disappear into a lava pit and the official consensus set of NOTAMs would continue to update.

Because this was all standardized back when interoperability meant standard fixed-length data formats that everyone had to understand rather than versioned API's and the inertia of the established file formats is too great.

Hell, if you _really_ wanted to insist on an exchange data format, XML would work just fine.