We broke records but I wouldn't consider it regular, not when we basically spent 10 years in the 90s with one british record but maybe I'm being too selective. And I mentioned the Glazers because you did, I don't think that there is a difference between the previous PLC, which isn't surprising since they were part of it, the main difference is that we got rid of the wage structure that prevented us from signing some players.
And I don't know if it's an interesting question, we kept spending relatively big with the likes of Hargreaves, Carrick, Nani, Anderson, Berbatov who were expensive players at the time, what we spent on Van Persie was important when you consider that he was in the last year of his contract. The main thing for me is that we didn't had a lot of room for new players until 2009-2010, we really messed up with the Ronaldo money.
Regarding our pre-Glazer spending I'd argue you are being far too selective. The only clubs who even come close to our spending in the 90s and early 00s were one or two Italian teams (Serie A was awash with cash at the time). Domestically we were light years ahead of the competition until Abramovic arrived, followed by the Glazers within two years, and a combination of petro dollars and Glazernomics turned the tide drastically.
In terms of statistics, I would repeat what I said previously- we held the domestic transfer record for 20 of the 25 years up to 2006. This wasn't just an anomalous large single deal either (like Newcastle signing Shearer and putting them top for a few years), we continually broke the record and pushed the British record higher during that period for players like Robson, Bruce, Cole, Ferdinand, Veron etc.
Your point about the wage structure is interesting- whilst you are correct that Ferguson made his frustrations with the wage structure well known, I would raise two points in defence- firstly, missing out on players is a fact of life for every team, and as angry as Ferguson presumaly got during the Giggs and Batistuta situations, it never really affected the on-field success of the team (we continued to be successful, attract world class talent and didn't lose players). Secondly, you only need to look at the state of the squad under Woodward's management to see what not having a consistent wage policy leads to. To use a contemporary example, I'm sure Liverpool's strict adherence to wage structure and policy of early contract renewals has seen them lose out of many a player (from memory I think this is why Goetze didn't sign?), and I'm sure there have been times when it has caused Klopp to spit feathers. However, it's also the reason why all of their important players are tied down to long-term contracts and is why they are able offer massive % increases to important players who deserve them (because their original wages were relatively meagre), which I'm sure helps for squad morale.
This post was much more long-winded than I was originally planning. The TLDR is that we were more financially dominant before the Glazers, and also that throwing our wage policy out of the window when Woodward came in is a big reason for the mess we're in now.
Pps- minor correction but the Glazers had less than 3% of shares and no decision making influence of the club prior to 2003, so the reason the PLC ran the way it did has nothing to do with Malcolm Glazer.