I don't think the editors of various publications necessarily rejected your letter because science was so greatly different in 1995, but perhaps because of errors in the content of the letter. However, you're quite right that our knowledge and perspectives of the universe have changed since then. New discoveries are happening so fast, that it's hard to set any specific markers, which is unlike the views of earlier discoveries which were held for long periods of time. That's because of the rapid pace of advancement in today's technology and communication.
Consider that the Hubble Space Telescope may be looking beyond our own Universe and seeing stars and galaxies that are part of a neighboring universe separated by billions of years or more. Perhaps in time we will discover some that are 50 to 100 billions years old. This leads us to the concept of multiple universes. Some may be closed universes, starting with a "Big Bang", expanding and then slowing down, contracting and collapsing on themselves. Others might be opened and always expanding and yet others may be in a steady state. What happens when a universe expands into a neighboring universe?
Is the Hubble Space Telescope looking beyond our universe and seeing stars and galaxies in a neighboring universe? Probably not. The reason is because the farther objects are, the faster they appear to be moving away. This is because space itself is expanding at increasing rates. The "horizon" of the observable universe is changing because of the continuing expansion of space. There are probably objects that are past the horizon, but we'll never see them and never know they were there.
Part of the reason for it has to do with what took place in the early universe before there were any stars or galaxies, during the Inflation Period. This period of inflation expanded faster than the speed of light. This gave the size of the universe a head start. It also means there were no stars or galaxies as the space was expanding during the Inflation Period. At a certain point in the distance, there would be nothing to see.
What we can see though, is the Cosmic Microwave Background. That pretty well indicates that whatever distant objects we can see are objects contained within the horizon of the observable universe.
In a multiverse scenario, if another universe were expanding into our own universe (assuming the other universe has stars and galaxies) we would see galaxies receding away from us because of the expansion of our universe, but we would also be able to see galaxies coming toward us from the expansion of the other universe. That doesn't seem to be happening with such distant objects.
Also, in a multiverse scenario, it's possible that a collision between two expanding universes might not be able to penetrate each other. Both would simply continue to expand. After all, what's to prevent them from expanding in a quantum foam of hyperspace? If one universe is older than the other, the older one would eventually fade out of existance making more room for the other to expand into or perhaps any new universes that may crop up.
If you haven't looked at it recently, I posted a couple of videos that might help visualize the origin of the universe. The first one looks at branes which would exist as a quantum foam much like a different kind of "universe" beyond our own universe. The video isn't two universes in collision, but is a visualization of two branes colliding within a field of 11 dimensions. The second vid called "Universe" tries to describe the quantum foam and the formation of the universe. In effect, what's beyond the universe is where the universe came from in the first place, and why we can never see beyond the horizon of the observable universe.
On the other side of the coin, the universe might be a tiny island within a much larger universe which in turn is part of an even larger universe, etc. This could almost (but not quite) fit with Fred Hoyle's Steady State theory, although Hoyle was not describing anything other than our own universe which seems clear is not a Steady State universe. If the universe were a closed universe, it would be infinite with no expansion. Rather Big Bangs can still occur, but sort of like an infinte progression of a turtle on the back of a turtle on the back of a turtle, etc.
The bottom line is that we have no real idea what kind of system our universe is a part of. We may develop various models that seem likely, but I doubt we'll ever really know.