Salary cap isn't a valid reason all teams have the same cap.
But not all teams have the same value of playing talent under the cap. For example, whatever we were paying Mahoney and Papali'i last year, it would be significantly less than what they are being paid this year, however they aren't significantly better players. In fact they might not be any better at all.
So if we had matched the offers from the Bulldogs/Tigers (respectively) we would be paying overs for these players, meaning the extra money used to pay them would have to come from other positions in the top 30, weakening the squad. Even if they had taken our offers it would still (probably) be an upgrade, so we would still have had to weaken other areas of the squad to keep them. This means our squad would (probably, depending on other signings) be weaker than last year, whether we kept those two or not. And even if we replaced them with players at value parity, if Mahoney and Papali'i were on unders last year (likely) and their replacements were worth exactly as much as their contracts, we are still replacing two starting players on unders with two starters not on unders.
This is how salary cap pressure works. The best clubs have more guys on unders and fewer guys on overs, while the weaker clubs are the other way around. The reasons for this are related to resources, not because Mark O'Neill (FFS!) suddenly didn't know how much merkins were worth.
Plus what salary cap pressure even you have just said today we had money left into he cap ffs...
We had money left in the cap because there were previously no merkins available for the amount we assessed them to be worth. So our options were to either pay more or just not sign them. Not signing those other merkins meant we had more to spend when players became available at reasonable prices.
Hodgson was injured and recovering when we signed him so no he isn't better.
Hodgson had recovered and was doing pre-season training when we signed him. He got injured after that.
Of course you have to have players ready to step up from juniors or have replacement in place the fact we signed Davey during the season shows our off season signings were poor.
The fact we had money to spend shows they were just backups on low salaries, which every club needs.