This could be a good topic in Off Topic this…
Everyone thinks that about everywhere. There are people from down South who even think Manchester and Liverpool accents are very similar with just the odd twang difference here and there.
But those different twangs are the difference between accents. From one place to another across the country there’s oniy a few twangs’ difference but spread that out over miles and that’s where different accents come in.
It’s like there’s only a few twangs different between a Scouse and Wirral or Southport accent and people who aren’t from over that way would mistake someone from Wirral or Southport as being Scouse if they weren’t used to those accents. That’s all you’ve done here.
Mancunians call Warringtonians ‘plastic Scousers’ because we think they sound Scouse. Scousers call Warringtonians ‘plastic Mancs’ because you think they sound Mancunian. The reality is they have their own specific accent that’s an in between of the two.
Everyone who’s from anywhere East of St Helens call Helenians ‘plastic Scousers’ because to many they sound Scouse (my Father cannot fathom that Johnny Vegas isn’t a Scouser, he thinks he’s got a full-on Scouse accent).
I can tell the difference between a Stockport and Oldham accent, a Bolton and Wigan accent, a Wigan and St Helens accent, a Leeds and a Barnsley and a Leeds and a Sheffield. They’re all different, some markedly different.
Take St Helens, from your examples. They call their town ‘Sint Elens’. A Mancunian calls St Helens ‘Sai-Elens’ (with a glottal stop between the two words).
Ask someone from Wigan to say, ‘did you hear that sound on the ground near the Crown&Anchor’ and then ask a Mancunian to say it and it sounds like a different language.
Ask a Loiner to say, ‘I didn’t know Joe was out in the snow’ and then ask a Mancunian to say it and, again, it sounds like a different language.
The Salford/Manchester accent is very specific compared to those you’ve said it sounds the same as.
Ask a Southerner to listen to a Mancunian and a Scouser say, ‘I didn’t know Joe was out in the snow’ and they would really struggle to tell the difference.
Although, young Mancunian lads don’t have a proper Salford/Manchester accent anymore. They sound more like the Londoners off Top Boy than they do Mancs. That new ‘belieeeve meee bro’ “Manchester”[but certainly not Manchester] accent is a proper abomination to the ears, they sound like twats. But the true Salford/Manchester accent is class and often ranks well above the Scouse accent in best accents in the country.