Maybe this is the wrong way to work it out
£20m over 4 year contract - £5m/year (4 years is usually the typical initial length, and Chelsea dont often buy players much under £20m)
&
£100k/week - £5m+
£10m+ /season/ new signing
I believe Chelsea are already the wrong side of FFP (although I seem to recall it isnt by much) - even with the few others possibly leaving in the summer, I cant see how they can do " a huge rebuilding" as you put it without ignoring FFP (mirroriing City lol)
.....even if they are lucky enough to be able to buy 4 players (of the quality they are likely to target in the main) that equate to the same cost of the four wages you indicated have or will leave
In regards to Utd, I doubt OShea, Brown (and definitely Scholes) would be on serious amounts /week (I only include Scholes because he is one of the few who would never ask /insist on a raise lol.....and I seem to recall last season it being stated he was on something relatively tiny like £80k/wk)
I've said it for years, Chelsea had a pretty decent squad back when Ranieri left including Robben and Cech, there was backup in most positions, several in form strikers. Mourinho got a few decent signings but mostly cack ones.
The strength in depth at Chelsea, for a team that has spent THAT much is laughable, truly laughable. Mourinho spent years trying anyone and getting rid of them a year later. How many Mourinho buys went on to be more than good enough, Tiago's been pretty decent, certainly better than a lot of midfielders, definately a good rotation option, 15mil in, 3-4mil on wages, out for 10mil a year later.
Then you've got tosh like Kalou and Malouda sucking down wages while he got rid of Robben, a guy who is so ridiculously better than both of them. I can't remember the timing but, though the Robben deal was a very good fee. not being able to persuade him to stay and Mourinho got fired a few months later?
Chelsea should both have a stronger squad, with better players and more depth. Instead like most of the top 6 they have a few excellent players, and too many average or even crap ones on massive wages rather than excellent players on massive wages, makes all the difference.
They should have by now had 5-10 Fabregas/Cleverly/Wilshire types come through over the past decade but they've had basically no one at all. Cheap players, they've been buying youth players but most of them have been no where near the level required. Had they bought a bunch of the available 16-18year olds, the right ones, they'd have half a squad of very cheap talented players, its a market Chelsea has probably missed, or utterly screwed up in more than any other top team in the world.
Also, Chelsea are in circa 70mil losses, they aren't close to breaking FFP. Torres cost a lot but its only 10mil a year on the books over 5 years, the transfer fee's spread over the years mean's they aren't a particularly substantial part of their losses, its wages, and they can't "fix" that problem without a new stadium, something their insanely ungrateful fans seem ignorant of. Abramovich saved them from bankruptcy, bought them titles, a team, ploughing billions into the club....... but now when he wants to spend another 200-300mil on a stadium they get picky because he wants to offset his losses by making a profit on the current stadiums land, why in the hell shouldn't he? "Here I've given your team 1.5-2billion after a new stadium, is it so bad that I offset the price of a stadium by making some profit on that land?" chelsea owners group "yeah, we want more money from you, you evil tight git you". It's honestly unbelievable.