The thing with Liverpool is they don't have great depth and they don't look to be strengthening this summer either. They have been fortunate with injuries but if say Salah, Mane get a serious one, they could be in serious trouble because those two are their main goalscorers. Can their youngsters step up next season? They are still unknown quantity at this point.
It is debatable whether they will be far ahead in the Top 2 next season, especially with the lack of depth. As we have seen with Man City and Liverpool (starting around February this year), a club can only sustain a high level performance and win games for so long before everything comes crashing down. They will be placed right up there by pundits, journalists etc next season because they are the champions and all that but whether they can produce another season like this or even last season remains to be seen.