Thank you for shining a light on this systemic vulnerability. I don't think organizations realize that, in many ways, they inherit the security of their service providers. As another commenter noted, the RMM is overdue for radical reinvention. Security-minded MSPs may need to think about delegated access to customer environments, privileged access workstations, or other methods for remotely administering customer environments without that big fat one-to-many target that RMM represents. I think the MSP tooling ecosystem is general is problematic - MSPs design for scale and efficiency (making them an economical option for customers as opposed to hiring internally), but do I really want my password manager integrated into my RMM? Maybe not... There's a lot of market share out there waiting for MSPs that can develop real cybersecurity maturity.
Managed services is the practice of outsourcing the responsibility for maintaining, and anticipating need for, a range of processes and functions in order to improve operations and cut expenses.[1][2] It is an alternative to the break/fix or on-demand outsourcing model where the service provider performs on-demand services and bills the customer only for the work done.[3][4]
DXC offers expertise for different industries and sectors as well as in key domain areas, including analytics, cloud and platform services, Internet of Things, and application services. A key offering is DXC Bionix, an approach built on intelligent automation at scale. It incorporates AI, lean process methodologies and an extensive partner network to automate workflows and improve response times, accuracy and standardization. DXC is heavily focused on emerging technologies, including blockchain, IoT, robotics and autonomous vehicles.
For over eight years, LME Services has been providing IT support for an accounting firm. They have applied their technical expertise uniformly to their services, including server assistance, hosting, and security. LME Services rapidly responds to mitigate any technical emergencies that arise. The client particularly appreciated the team's consistent reliability. 
Managed services and outsourcing works exactly the same. However managed IT services and traditional IT services are different. Pay attention to the words managed and tradition outsourcing given. It is basically obtaining services from a third party. There are different ways of observing one is traditional IT services the other one has managed IT services. So basically these two are different models through which IT services are outsourced.
Backup and Disaster Recovery (BDR)—a combination of data backup and disaster-recovery solutions that works cohesively to ensure an organization's critical business functions will continue to operate despite serious incidents or disasters that might otherwise have interrupted them, or will be recovered to an operational state within a reasonably short period.