The problem is the ideologues making up the "conservative base". The so-called conservative base of the Republican party is relatively small. The fact is, the base needs moderates and independents if they ever expect to win another national election.
I disagree.
The conservative base is at least 25%, probably 33%, possibly as high as 40%.
You will need those 25 to 40% of "relatively small" base to win in November.
Their just aren't enough moderates and independents out there to cover those types of percentages, and they tend to split both ways, anyway.
Let's say you may be half right, and you will need moderates and independents,you will probably need both.
If you ignore, ridicule, or anger the conservative base, you will lose for certain.
The conservative base are the people most likely to get involved and actively campaign.
The moderates and independents, not so much.