Our situation is awful, and it wont improve that much.
No, the rise of the oil clubs and inflation that comes with it, means we cant actually buy big stars anymore.
Not too mention that Barca has proven to be in auto-pilot mode in la liga, even without Messi, its not a serious competition for them anymore, la liga is essentially their playground, much like Serie A is for Juventus.
So, we wont have to financial strength to keep up with the rich oil clubs in Europe (PSG has to stop choking at some point), and domestically is basically a hopeless situation, we are screwed for years to come.
PSG has already been dealt with thanks to retroactive decrease of our sponsors. When we bought the players, it was ok for UEFA to consider our contracts were worth 100 M but then they wanted to sanction us by changing that value for years that had already ended. This is why PSG had to sell players like Lo Celso, Guedes, etc. When you see when they are doing in la Liga (Guedes was playing injured before his operation), PSG would have been way more threatening even after Cavani and Neymar injuries.
You have to differentiate PSG and City. Look at how many players PSG had to sell compared to City, just because City has british TV rights money. With the current QTA valuation by UEFA, there is no more inflated contract. In fact, UEFA wants PSG to not renew this contract at all, so it is hard to call it an "oil" club. PSG is poorer than when they bought Neymar and Mbappé actually. Our saving line is that we got a new principal sponsor for 60-75 M€ and Nike is going to give us 75 M€ (with apparently a lot of sporting bonuses that can bring it up to 100 M+) and Jordan collaboration that is working fire (15 M€ was the expected return for the club but it is more successful than predicted so we will get more). And all that still doesn't make up entirely for the QTA contract loss but UEFA can't annoy us anymore since those contracts are not considered related parties with Qatar.
It is only next year (not 2019/2020 but 2020/2021) that we will see a big increase in TV rights and PSG will be able to invest on the market i think. Also, remember PSG being in French league has less TV rights money, is the club paying the most taxes in the whole world and can't develop their revenues via the stadium like most of the top european clubs nowadays (Juve, City, Arsenal, Tottenham etc. and soon Milan clubs, Real, Barca).
Barcelona has done better business than Real Madrid, i agree. They have bought a lot of young players, already good despite their youth : Dembélé, Ter Stegen before, Lenglet, Malcom, Arthur, de Jong, de Ligt probably. They have a good axis for a team in the next 5/10 years. However, we can't gauge the effect Messi retirement will have. They'll have a lot of money to invest at that moment though but Messi is only one of a kind.
As for Madrid, you have reportedly 500 M to invest and your new stadium will be a cash cow. Realistically, only Barca, City and MU (if they want) can compete with you financially.