Is it really better for most companies to have both an MSP and an internal IT person?

The honest answer is that the pairing is excellent for some businesses and an unnecessary expense for most. For a typical small business (under roughly 40 to 50 employees, standard office technology), a good MSP alone provides the monitoring, security, help desk, and strategy the business needs, at a fraction of what an IT salary costs. Adding an internal hire at that size usually buys convenience, not capability.

The equation changes with scale and complexity. Once a business has enough daily hands-on need (hundreds of devices, specialized line-of-business systems, a warehouse floor, constant onboarding), an internal person earns their keep on responsiveness and institutional knowledge, and the MSP shifts to what individuals cannot provide alone: 24/7 monitoring, an enterprise security stack, backup infrastructure, deep expertise on call, and vacation-proof coverage. That combination is co-managed IT, and at the right size it is genuinely the strongest model.

So the practical guidance: if you have no internal IT today, do not hire one just to pair with an MSP; let the MSP carry it and revisit when scale demands. If you already have a good internal person, do not assume an MSP replaces them; the right provider will structure around them. Beware of absolutes in either direction from anyone selling you something.