We cannot see other universes because the light they emit is red shifted so much we are unable to detect it. (If we can detect gravitational waves, it won't be long before we will be able to see that super red shifted light) But we are pretty certain they are there. Now... a super massive black hole (SMBH) will not evaporate for 100s of millions of years. In that time, it is very possible for it to "run into" another SMBH that left some other universe I believe, if their combined mass is close to the Plank Limit ( the entire mass and energy in our universe ), the collision should create a brand new universe: therefore. maintaining the continuity of the multi-verse.
I invite everyone to collaborate this thought with me.
Thank you for your attention.