The man's appointment as Wallabies coach last November seems a lifetime ago.
His public relations tour two months later looked a smash hit and Rugby Australia (RA) were rightly praised for securing the services of a man much better equipped for international head coaching than the bloke New Zealand Rugby (NZR) had foisted on All Blacks fans.
Now, holed up in Scotland, Rennie must look at reports from Australia and wonder if his contract's worth the paper it's written on.
Turmoil seems a fair enough word to describe rugby in Australia, as the game goes broke and the disenchanted and disaffected seek to apportion blame.
Raelene Castle, the beleaguered RA chief executive, appears as if she won't be the only casualty of a media company's desire to exert its authority.
News Limited, via its newspaper and online arms, is at war with Castle and RA and determined to insert one of its own – Phil Kearns – in her place. Fair enough, but as things stand it wouldn't really matter who was at the helm.
The problems with the game in Australia run far, far deeper than the chief executive of RA and won't be fixed in a hurry.
No, Castle probably hasn't done a great job of reviving Australia's Super Rugby fortunes, or handling men such as Israel Folau and Michael Cheika, but there's only so much an administrator can do in the short to medium term when the game is fundamentally weak.
The AFL will emerge from the Covid-19 pandemic in decent shape, while rugby league has suddenly become the cohesive and cocky force we once knew. For all we know, it might well become the first competition of substance to resume relatively intact.
It doesn't hurt that there's a media company driving talk of this rugby league revival. The same company, ironically, which appears so hellbent on aiding rugby's demise.
That's what you get when you walk away from the broadcast-rights negotiating table, as RA did to Fox a couple of months back.
All of which must worry Rennie, along with fans on this side of the Tasman too.
Castle has dismissed a lot of this stuff as "noise'' but things have been pretty noisy in Australia for a while now and, if nothing else, will hardly aid the Wallabies' cause when Bledisloe Cup rugby eventually resumes.
We all get that rugby will be regional, rather than international, when we finally get it back. Whether it be in franchise, provincial, club, North-South or Probables v Possibles guises, New Zealand's best will begin competing in time.
But when they do, it won't be long before eyes turn to Australia.
South Africa and Japan and Europe now look quite a long way away, in this new world order. If the All Blacks – or Silver Ferns and Black Caps and Kiwis for that matter – do start playing fixtures again, it feels fair to assume they'll be against Australia.
When that happens, those Aussie netball, cricket and rugby league sides are likely to be as formidable as ever, but not the Wallabies.
Frankly, we need them to be outstanding again. To be as tough and arrogant and, occasionally, unlikeable as the sides Alan Jones, Bob Dwyer, Rod McQueen and Eddie Jones once coached. To bring intrigue and unpredictability to an annual Bledisloe Cup series that has gradually become a contest in name only.
Sure, Cheika and co cleaned the All Blacks up in Perth last year. But that was once and certainly not sufficient to wrest the trophy back.
Rennie's appointment, allied to that of Ian Foster here, brought with it great optimism. Australia might not have as good a players as us, but their coach was better (and more popular) and there was a sense the outcome of these games could become uncertain again.
But as RA continues to stumble at every hurdle, and more and more prominent folk seek to discredit them, the more we all lose out. Not just Rennie and the players and the various people who sponsor the game in Australia, but the All Blacks and we fans too.