Liverpool's transfer record is much worse than United's over the last 5 years, over the last 10 years, over the last 20 years, whatever way you want to look at it, net spend, gross spend, weighted spend.
I don't think a single club can lay claim to having wasted as much money as Liverpool. Your transfer record is abysmal. Rodgers fail rate was about 90%. Even his small number of successes are asterisked.
Over the long term I pretty much agree with you. We have wasted a huge amount of money. But my initial post on this was more concerned with the players bought under Rodgers & LvG+Moyes and in that regard I'd strongly dispute calling it abysmal. It should be noted I'm not a Rodgers apologist and was more than happy to see him go, he had been given more than a fair chance (though the timing of his departure was off).
As far as Rodgers goes let's concentrate on players of over 10M and up because realistically anyone under that (talking PL not the rest of Europe) in this day and age is either a gamble or bought solely as a squad player. We can also exclude Loan players (4 on that list) who by their nature are generally squad fillers (although when we are talking about players such as Falcao costing ca. 12-15M in salary alone that is a slightly different matter) and there are 3 Free transfers on that list.
1) Complete gambles or squad fillers (by being under 5M) - all top teams frequently buy players of this ilk and keep them in the youth or reserve teams hoping they will make the step up : 5 players inc. Ings who may end up costing anywhere from 4-7M. In this bracket we either got our money back, made a profit or the player ended up being worth the money and gamble. So nothing abysmal there.
2) Players on the cheap but still a gamble (by being 5M+ to -10M) : 7 players (this includes Coutinho, Gomez, Origi & Mignolet, so either value for money or promising youngsters). 3 others that we lost a little on but not a lot, otherwise the money could and should have been better spent. But again nothing abysmal, or even poor, there.
3) Total Waste of time & money : Borini (10.5), Balotelli (16), Allen (15), Lovren (20m). Yep, abysmal.
4) Qualified or Unqualified successes costing over 10M (6 players) : Sturridge (12m), Sakho (18m), Can (9.75 - a youngster for the future, there's no way we could fail to at the very least get our money back if we decided to sell at any time), Lallana (25m - we clearly considerably overpaid but regardless is a regular and under Klopp could become a much larger contributor and can not be considered a failure as a player). Moreno (12M - a young and improving player), Clyne (12.5M and arguably our Player of the Season so far). Actually on balance pretty damn good.
5) Jury's still out due to new arrival, settling in, Rodgers Out/Klopp In and simply far too few games played : Benteke (32m) and Firmino (29m). Both big successes at their previous clubs so no reason why they shouldn't replicate that. Markovic (19.8m), represents a major gamble on a very highly rated youngster. We'll see what happens when Klopp gets his hands on him since Rodgers perpetually played him out of position.
It should be remembered that 3 years ago we had a small squad and had to enlarge it, however some squad players, I think it is fair to say, played more often, due to injuries to key players (Liverpool having consistency been close to the top of most playing days lost to injuries over the past few years, and we're bang at the top of that injury table again this season), than would have been expected when we bought them as squad fillers.
Therefore looking at the above did we actually waste money ? Well undoubtedly there are some key failures but there are also successes (outstanding are Coutinho at 7M and Sturbridge at 12M) to go along with those notable failures. However is that different to any other manager and in this instance I was specifically mentioning LvG and Moyes : De Maria at 60M, Fellaini at 29m, has Depay looked even just likely to live up to his 25m fee yet, Martial was a huge panic buy due to the failure to secure Muller or another top striker and we have to see how he gets on over a full season (great start though), Romero, Valdes (Free), Jones - arguments could be made against all of those three, even (much as I really like them) Schneiderlin & Schweinsteiger have not lived up to their form at their previous clubs yet, being used so defensively by LvG and also is Herrera worth 29M ? That may be arguable under LvG this season who doesn't seem to like/play him as much as I thought he deserves to play.
It's difficult to say categorically that Rodgers wasted our money with at least 10 players being qualified successes or better, others sold for a profit and others living up to the (small) fee paid for them. And therein lies the crux of the matter, I've said before that, although 3 years ago we needed to enlarge the squad, I'd have preferred we did it by spending well on 2-3 1st team players per season and stacking the rest of the squad places with youngsters from the reserves, rather than spending 20-25m on cheap gambles but that's still petty change in terms of our 3 years' budget. The real waste was 60m+ on 4 players that contributed very little and in overpaying for Lallana, Lovren, Allen & Balotelli (though it's something United, Chelsea, Spurs and City also do regularly, with the PL Tax).