Historically they have been but most innovation at least from bmw comes from slapping extra turbos to chase ever increasing bhp. Interiors are mainly the same but with updated instrument clusters and redesigned exteriors. Not groundbreaking i think what is happening is too much attention to short term profits and forcing customers to refresh their cars every few years. Literally after they out of warranty bmws fall apart not to mention mercedeses that fall apparent even within warranty (the m and s class do).
BMW has never had great longevity. They're mostly fine for 100k miles, but people expect cars to last much longer than that now. Old BMWs have solid reputation as a money pit.
They're getting to be far too complex to be reliable, and too much attention is paid to short term profits (IMO), so we get what we have now.