They have worked recently to implement a self-hosted tax submission system and given their rate of return while there may be some mismanagement it is one of the most provably efficient organizations in the government netting 415$ for every dollar of funding in 2024.

They built IRS Direct File which was a huge improvement. Then the administration killed it to serve tax prep companies.

They have 150 million paying "customers" (not including businesses) and bring in $5 trillion+ yearly.

The public sector is where you need 12 people (and a project manager) to build an Access database.