Formerly computers had a special key "РУС" so that the layout could be switched. They also had more alphabet keys so that it was possible to put the punctuation in Russian layout at the same places as in Latin layout. For example, this is a keyboard of Yamaha computer from the mid-80s (it was the first computer model I ever used):
Unfortunately, in mid-1990s we saw dramatic spread of the American standard of computers, whose keyboard has no features to support languages other than English. So now we have to press two keys (usually Alt+Shift simultaniously) to switch the layout (or those who uses Linux can employ Caps Lock for that). These keys were never intended for layout switching. American keyboard standard also has smaller number of keys so that dot, comma, question sign and other punctuation are located in different places in Russian in English layouts. When entering Russian text we have to use Shift key to enter such usual character as comma. And we have no possibility to enter some characters such as {, [, ], }, #, @, & in Russian layout at all. This is very annoying if you have to enter a text with these characters: you have to switch the layout after each word.
Possibly the fact that computers from 1980s (even imported) had better support for Russian language can be explained with stronger position of Soviet government that required all computers to be adapter for Russian well.