Actual salaries haven't fallen. The point of paying those salaries is you have to earn every penny. If they overhire and a bunch of people start taking the money for granted, that breaks down the social contract
Half of the perks e.g. sabbaticals or sleeping pods don't even make sense in a competitive working environment
Your base salary won't tend to drop but at the same time you'll get an annual 1.5% increase when inflation is 9% and the company made $300 billion in profits last year.
Bonuses for normal employees (below VP) are essentially formulaic at most big tech companies, for the most part. So if you're a senior SWE with a 15% bonus target, well that's based on yoru base salary. It hasn't gone down in nominal terms but it has in real terms.
Also, depending on your company, there's a pool of discretionary funds on top of the formula. Your bonus can even be taken away and given to someone else on the team (yes, this happens). How big is that pool? Has it increased over time? Decreased? Or stayed the same? On a per-employee basis. You don't have visibility into that unless you're a manager.
Next is stock compensation. Your initial grant is obviously known. Annual refreshes if you get them tend to be formulaic too. But what about discretionary grants? That's where the big money is. How much is being thrown around in total? Is it going up or down over time? You have no visibility into that.
All of the above have, as input, your performance ratings. There are quotas for each performance level at a certain level (usually 150+ people or director level) so not everyone gets Greatly Exceeds Expectations. What are the quotas ("target percentages") for each bucket? Has that changed over time? Some compoanies now have targets for subpar ratings (ie ratings below "Meets Expectations"). It's the pipeline for getting rid of people and getting people to do more for the same money.
So technically you have to do more now to maintain a Meets Expectation rating than you did 5 or 10 years ago. Is that a pay cut?
And then we have promotions. The typical way this works is a company will divide promotion candidates into pools. A promotion committee will essentially rank the packets they have. At a certain level there is a quota for promotions to hand out. Those get distributed to those from the top down until there are no promotions left to give out.
Companies have allegedly reduced costs by simply reducing the promotion target percentages / quotas.
And then there are all the benefits that have a tendency to get worse over time. Health sinsurance, 401k matching and less tangible benefits like food, facilities and so on.
But supposing this happens across the economy, there's less inflation. E.g. if housing costs track tech salaries and soak up most of the surplus available, the relative wealth gained/lost is hard to predict
Half of the perks e.g. sabbaticals or sleeping pods don't even make sense in a competitive working environment