It’s a bit more complex than that. Intel CPUs (to this day) boot in real mode, which is what DOS is using. In this mode, the system only has access to 640k of RAM. Windows 95 and later switch the processor to protected mode, where the system gets access to all of the RAM and also to memory protection features, so processes can’t real and write each other’s memory. However, in this mode it’s impossible to run real mode code, such as the one provided by DOS.
DOS games had a trick where they briefly switched back to real mode to execute DOS functions (mostly reading and writing to disk) and then back to protected mode, but I don’t think that Windows 95 did that.