As mentioned by psi81, many won't apply although if the shareprice rises that will change.
A few other points are:
Say the top 100 holders have 50% of the company, they could subscribe for 6m new shares (whoopee!! for them) or around 1% of their holding. They are getting the shaft and Mitch Dawney is getting the shaft. Probably the top 100 own more than that.
That leaves a lot for the little guys but if you are holding 2,000 shares there's little point subscribing for another 30,000 as any scale back would occur pro-rata.
Many of the smaller shareholdings won't get much if scaling back is required.
I have 65,000 shares and will apply for 30,000 new shares - even if the offer is oversubscribed I expect to maintain or increase my proportional holding. Will see how it plays out.