Before Sheffield Supertram:
Middlewood had a better than ten minute frequency into the city centre via Hillsborough (double deckers on the SYT 81-84, 88, plus competition from the likes of sut), downgraded to a ten minute minibus, which was then cut to just a Middlewood - Hillsborough shuttle. There were frequent buses on the SYT 79/89 (779/789) from nearby Leppings Lane via Hillsborough to the city centre, there was the competing SYT 17 and Sheffield Omnibus 18 on that corridor too.
Now there's just the 57, running every sixty five or so minutes from Middlewood to Hillsborough and the city centre, plus the tendered 31 every hour from Leppings Lane (which runs via the back roads into the city centre)
Malin Bridge had something like a five minute service to Hillsborough and the city centre (85-87, later replaced by the diverted 81-84). Now there's just three or four buses an hour on the 81/82, thanks to First's AI timetabling
(Other routes from Hillsborough direct into the city centre have been similarly cut, Widewood and Loxley had a six minute minibus on the 13/14 into town, now replaced by a half hourly 52A that takes a long diversion)
Norfolk Park had about fourteen buses an hour (SYT 70/71/771, Terrier 10/11), now there are no buses
City - Birley - Crystal Peaks had competition, the SYT 146 vs the South Riding 46 (plus the SYT 63 on the city side). Now there's just one bus an hour from town to Birley on the 8, which connects with the tendered half hourly minibuses on the M45/46
Halfway had a ten minute express service to Sheffield on the X55, plus other fast services via Mosbrough (X51, X52 etc). Now there's only the all-stops 120 every fifteen minutes
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Elsewhere, Alloa used to have a fairly frequent service into Stirling, the 60 and the 62/63 circular were every ten minutes along the main road. Plus the hourly 14 from Dunfermline that ran this way too. And did the 15 run this way (Falkirk - Alloa - Stirling), plus the X18? Now, there's just the half hourly 52 (and the relatively recently introduced Stagecoach X22 every hour)
Bathgate used to have a good service into Edinburgh, including the twenty minute 16/17/16. Cuts made by Eastern Scottish/ First once the rail line was reopened saw no buses along the main road (services diverted via central Livingston instead, with a hefty time penalty). One positive of the recent bus was was that Lothian rebuilt that market with a half hourly X18
One other feature of the Borders line was the scrapping of the long established direct bus from Gorebridge - Dalkeith - Edinburgh. Now there's just the 29, which avoids Dalkeith