The land was never the problem, it was the ability to get goods to market. British settlers wanted to be able to make money (so did the French), but the big difference was the English had other places to go that spoke English, where the French didn't. The segneurial system favoured whoever had the most cash, the English, and the French figured out early on that any opening of new land opened it up to more English settlement which is why they continually battled the legislature over development money for roads and canals. If the land opens up earlier, the British settlers will come in and drown out the French. Not everywhere in Lower Canada, but Montreal and the surrounding area will be solidly Anglo by 1880 as you get further East the Anglo numbers will decline until Quebec City which would be a mixture of French and English.
Would that really happen? Why wouldn't French Canadian migrants take advantage of the newly-opened lands in Lower Canada, too?