I think Lamps put it well, this whole he turned us down is speculation that doesn’t even look right. Forest were in the championship and paid £1-2M for him from Walsall when we were in League 1 and Northampton with greats like Adam Barton in midfield and only signing shit free agents and loans.
In summer 2016 he went to Bristol City in the championship, and we were beginning our descent to League 2 with Mogga losing the plot and assembling arguably the worst squad in football history (Stuart Beavon, Kevin Foley, Adeyai) after banking on PL loans that never came in.
The only time it looks like there could have been a chance of us being in a biddable position (or even the same league) was 2021 when he went to Swansea on a free. But look at who we signed that summer permanently and maybe we wouldn’t have been guaranteeing a regular starting position.
To people slagging saying he rejected us, is based just on social media speculation when it looks unlikely the club would have been unable to make a move for most of his career.