Not removed. The enhanced taskbar is still in 2.8, and the 2.8 changelog carries fixes that touch it directly, including one for the start button when the enhanced taskbar is not enabled.
What I would check first is whether Start11's taskbar features have been switched off wholesale. 2.7 added an option that disables all of Start11's taskbar functionality, and while that is in effect the enhanced taskbar and everything under it, combining included, is not offered at all.
There is a registry value that does the same job: S11_BLOCKMOSTTASK, under HKEY_CURRENT_USER\SOFTWARE\Stardock\Start8\Start8.ini\Start8. If it is there and set to 1, clear it and then restart Explorer, because that one needs an Explorer restart rather than just a settings reload.
One thing about the purge: if you restored a settings backup after the reinstall, that would put the same value straight back, which makes a clean install look like it changed nothing.