The uplift as it is now is unlikely to attract massive numbers of people, 8 runs from a 9am start to a 4pm last run means about a 40minute turnaround time for a 5 min downhill, inc drivers' lunchbreak. Not a satisfactory way to get people up a hill.
I use the uplift from time to time as although you can just about push/ride to the top in 40 min you're knackered after a couple of runs(unless you're gluptonesque in terms of uphill prowess). However I find the uphill in the bus quite tedious and don't really want to spend the time I'm allowed to spend away from the family sat in a bus, however good the trails downhill are.
If a chairlift was put in it would be a massive success imo, cut the uphill to say 6-7 minutes and people would flock to use it.
I would certainly use it every week as I'm sure many others would and with the right business plan ie blue, red, freeride trails, cafe, bikeshop etc, like a DH Glentress it would really take off.
I remember going to Glentress ten years ago, there were a handfull of cars (if any) in the car park, no bike shop or cafe and look at it now, new large visitor facilities about to be opened and people flocking there every week. If the business plan for GT eight or so years ago had been based on the existing rider numbers there would never have been a business case to open a cafe and develope the trails, the FC thought that there was a market out there if the facilities wer put in and they were right.
Innerleithen is at this point just now I'd say, someone needs to take a leap of faith and put the infrastructure in place.
'Build it and they will come'