To me, the name non-denom is just an excuse to break away and start a church that is not accountable to anyone. We had a few non-denom pastors take courses at Seminary. It always seemed like they wanted control, and they had a lot of weird doctrines they could not back up with Scripture.
I attended non-denoms when I was first saved. They seemed to split with amazing regularity and someone set themselves up as the new prophet or authority from God.
I was very glad to get out of those kinds of churches. Being a Baptist is the best of both worlds. You are basically independent, but affiliated for purposes of mission, and training. But even the Southern Baptists go from one end to the other regarding eschatology, soteriology and church government. The SBC has become a little too hierarchical in the US, but in Canada they still run the churches independently. However, they do support each other, and make decisions regarding the future of the convention.
I have been in 3 Baptist conventions, working my way to one that is both near my home and that I agree with doctrinally since I moved.
I will say that in Canada, the mainline churches are mostly empty. It is the evangelical churches that are still growing because they are reaching out to the communities and preaching the gospel. That includes Pentecostal and Evangelical Lutheran, and Evangelical Free, most Baptist churches and C&MA and a few others.
Canada used to have a big mainline denomination called the United Church of Canada. It was the union of some Presbyterian Churches, Methodist and some Congregationalist Churches. It has lost millions of members as they have become totally humanist and "inclusive" meaning more worried about gay rights than sin and Jesus dying on the cross. As for the RCC, it is really archaic and has lost its support base in Quebec. Anglicans still exist, but if my aunt is any indication, it has definitely slid to the left. Not sure about the Missouri Synod, I know a few people in it, but I cannot vouch for the growth rate, either up or down.