Just do this already.
The Bitcoin chain that only allows 2-5 million people really using it will quickly die as people migrate to the 20 mb one simply in order to actually USE Bitcoin.
To begin with those opposed to the change is only 40%, screw them. They'll change their minds in a week.
The number opposed is just 20%. The other 20% is like...
whatever.
Bitcoin can have the lion's share at the top of the Pareto distribution, but we should expect a long tail of other crypto with varying degrees of suitability for substitution. If people prefer to use coins based on a silly picture of a dog or constellations of prime numbers, they will. You need to accept that and move on.
The problem is that the 1MB limit is just so small that eventually Bitcoin would be way down in the long tail of the Pareto distribution, behind even Litecoin which has 4x the volume capacity, and the silly-dog-picture-coin which has 10x the volume capacity of Bitcoin.
Is that what we want and expect of the No.1 cryptocurrency? In fact it can't remain No.1 the way it is.