Dell still makes money off their personal computers, but the margins are simply way higher when selling to corporate. Personal computers have a huge amount of competition and support is expensive.
And though iPads are probably hurting Dell somewhat, I suspect the effect is a little different from 'people switching to tablets'. Rather, most people don't have money to afford both a new iPad and a new PC. While in the past, upgrading ones PC every few years has often been a given, many people will pick the iPad over the the new computer if upgrading doesn't really seem to offer much value in comparison.
They'll keep using their PC -- it's just that they're not buying a new one from Dell.
The low-end PC market is very saturated and very low-margin; even if Dell still has a lot of sales, they're going to talk about the thing that makes them the most profit.