Ubuntu 10.04 compares favourably with Windows 7 and OS/X, its competition.
It falls down on gaming, but that is another issue. Using your assumption,
then Windows 7 should be as comparably fast as Windows 95 was in its time
and so on. As we know that isn't the case. We can do things on our computers
not even dreamed of in those days, multi-tasking, running virtual machines,
video editing, streaming multi-media, HDR photography, social media, VOIP,
etc. As we add multi-core processors and more RAM we always raise the bar
and demand more of our computers.

I have been using desktop computers since in 1982 and have always run my
computers at an extreme whether it was my first Apple II or my netbook. As
the computers got more sophisticated, then I pushed things to even more
extremes. Users are always pushing the envelope.

As new things come along and users want them, then the kernel which is
relatively small grows. More libraries and dependencies are added. When my
computer boots it loads many daemons from Bluetooth support to cryptography
plus it mounts several different devices and file systems. Life is no longer
the same and we can not compare today with simpler times.

I remember when we were told that the next generation would work a 30 hour
work week and have lots of leisure time. The opposite has happened. We work
more, don't get as much vacation time, don't get enough sleep and bosses
demand that we be ever more productive. In the brave new world we are
plugged in like at no time and we keep on buying more. We live in a consumer
society and operating systems have tried to keep up. I don't blame Microsoft
and Apple. We can't turn back the clock, but we can tune out.

What you call bloatware may be just a case of running the wrong OS. There
are alternatives in the Linux world. If you want a faster, leaner system
then you should run something like Arch which only adds what you want
instead of Ubuntu.