Like many things, also a case of diminishing returns on price you pay for things too. No player is '3 times better than anyone', ... although not sure exactly how you'd quantify that anyway...? Some people pay 10k for a racing cycle, I doubt it makes you 20 times faster than a £500 bike though.
Anyway, not sure he's ready to take the PL by storm this season, although you never know. Good player for the future, a lot higher ceiling than Lowe, in terms of potential. Semenyo costs that as everything points to someone who 'may' become a good PL player, with right coaching, atttidue etc. Don't think Lowe has ever been considered a PL player, in terms of ability or potential.
Good piece of business imo, exciting prospect from English leagues, rather than entire squad being assembled from abroad.