I don't think the current Pool has it in them to make it a dynasty sort of thing, like people are fearing. As they get bigger, these Mane and Salah type deals would be tougher to find as clubs will look to charge them a higher amount, something I don't think their finances allow. Even, if we do account for increased sponsorship due to rise in stature, they'd first have to negotiate much better deals with their players rather.
Add to that, their entire side is basically of the same age group - VVD, Salah, Mane, Firmino are all 28 and considering a major part of their game is based on pace and they play a high tempo game, one has to wonder, how long will they last.
Coming to Chelsea, they are building a pretty good side, I'd have to admit and like United are building it the right way. However, I fear that their defence is a bit too shaky. Instead of signing Werner, I'd probably have gone for a CB as Rudiger apart (who himself is injury prone), their CBs aren't really that good. Azpi is on his last legs as well and Alonso is well just not good enough while defending
We, ourselves, are a weird case. I'd say if we can add a RW, CDM and a CB this summer and then focus on adding depth to the side the next summer, I'd fancy us to probably dominate the league for a few years. Most of our players are in their early twenties and would have reached around 24-25 years of age when we're completely done with our squad building. This would mean that us, like Chelsea (provided they sign defenders of the right age), would be best placed for a title challenge in the next few years.