Whether flow is 6 years, 8 years, or 10 years; it will not be 25 years as it has been in the past. You will not get gray hair and go balding working for Envoy (unless you want to be a lifer), as pilots have in the past.
If you look at the hiring rates projected across the majors in a few years, and figure how many will come from regionals, it will not be on the upper end of that number of years range. There are 20,000 regional pilots. In 2018, the majors will hire between 4,000 - 5,000 for the year. It will go up from there according to the Boeing report they put out in 2016.
Some will continue to come direct from the military, some will come from commercial aviation, but with that rate most will come from the regionals.
There will continue to be flows, but there will be an increasing number of pilots hired OTS, both from other regionals and those that have flows. Things are going to change in the regional world over the next few years. There are just too many hires for the current model, at the current size, to remain viable. These changes will bode well for the bulk of the regional pilots wanting to get hired by the majors.